Add latest changes from gitlab-org/gitlab@15-3-stable-eev15.3.0-rc42

7 files changed, 2438 insertions, 218 deletions

diff --git a/glfm_specification/example_snapshots/examples_index.yml b/glfm_specification/example_snapshots/examples_index.yml
index 9b601460b1d..5778819e024 100644
--- a/glfm_specification/example_snapshots/examples_index.yml
+++ b/glfm_specification/example_snapshots/examples_index.yml
@@ -2015,3 +2015,30 @@
 07_01__gitlab_specific_markdown__footnotes__001:
   spec_txt_example_position: 674
   source_specification: gitlab
+07_02__gitlab_specific_markdown__task_list_items__001:
+  spec_txt_example_position: 675
+  source_specification: gitlab
+07_02__gitlab_specific_markdown__task_list_items__002:
+  spec_txt_example_position: 676
+  source_specification: gitlab
+07_02__gitlab_specific_markdown__task_list_items__003:
+  spec_txt_example_position: 677
+  source_specification: gitlab
+07_02__gitlab_specific_markdown__task_list_items__004:
+  spec_txt_example_position: 678
+  source_specification: gitlab
+07_03__gitlab_specific_markdown__front_matter__001:
+  spec_txt_example_position: 679
+  source_specification: gitlab
+07_03__gitlab_specific_markdown__front_matter__002:
+  spec_txt_example_position: 680
+  source_specification: gitlab
+07_03__gitlab_specific_markdown__front_matter__003:
+  spec_txt_example_position: 681
+  source_specification: gitlab
+07_03__gitlab_specific_markdown__front_matter__004:
+  spec_txt_example_position: 682
+  source_specification: gitlab
+07_03__gitlab_specific_markdown__front_matter__005:
+  spec_txt_example_position: 683
+  source_specification: gitlab
diff --git a/glfm_specification/example_snapshots/html.yml b/glfm_specification/example_snapshots/html.yml
index 6c05fbe744b..eda78a29da4 100644
--- a/glfm_specification/example_snapshots/html.yml
+++ b/glfm_specification/example_snapshots/html.yml
@@ -813,8 +813,7 @@
     <a id="user-content-bar" class="anchor" href="#bar" aria-hidden="true"></a>Bar</h2>
     <p data-sourcepos="6:1-6:3" dir="auto">Baz</p>
   wysiwyg: |-
-    <hr>
-    <h2>Foo</h2>
+    <pre language="yaml" class="content-editor-code-block undefined code highlight" isfrontmatter="true"><code>Foo</code></pre>
     <h2>Bar</h2>
     <p>Baz</p>
 04_03__leaf_blocks__setext_headings__018:
@@ -834,8 +833,7 @@
     <copy-code></copy-code>
     </div>
   wysiwyg: |-
-    <hr>
-    <hr>
+    <pre language="yaml" class="content-editor-code-block undefined code highlight" isfrontmatter="true"><code></code></pre>
 04_03__leaf_blocks__setext_headings__020:
   canonical: |
     <ul>
@@ -2144,6 +2142,7 @@
   static: |-
     <p data-sourcepos="3:1-3:5" dir="auto"><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url "title"</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__002:
   canonical: |
@@ -2151,6 +2150,7 @@
   static: |-
     <p data-sourcepos="5:1-5:5" dir="auto"><a href="/url" title="the title">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url "the title"</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="the title">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__003:
   canonical: |
@@ -2158,6 +2158,7 @@
   static: |-
     <p data-sourcepos="3:1-3:11" dir="auto"><a href="my_(url)" title="title (with parens)">Foo*bar]</a></p>
   wysiwyg: |-
+    <pre>[foo*bar\]]: my_(url) "title (with parens)"</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="my_(url)" title="title (with parens)">Foo*bar]</a></p>
 04_07__leaf_blocks__link_reference_definitions__004:
   canonical: |
@@ -2165,6 +2166,7 @@
   static: |-
     <p data-sourcepos="5:1-5:9" dir="auto"><a href="my%20url" title="title">Foo bar</a></p>
   wysiwyg: |-
+    <pre>[foo bar]: my url "title"</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="my%20url" title="title">Foo bar</a></p>
 04_07__leaf_blocks__link_reference_definitions__005:
   canonical: |
@@ -2180,6 +2182,11 @@
     line2
     ">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url "
+    title
+    line1
+    line2
+    "</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="
     title
     line1
@@ -2204,6 +2211,7 @@
   static: |-
     <p data-sourcepos="4:1-4:5" dir="auto"><a href="/url">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__008:
   canonical: |
@@ -2221,6 +2229,7 @@
   static: |-
     <p data-sourcepos="3:1-3:5" dir="auto"><a href="">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: </pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__010:
   canonical: |
@@ -2238,6 +2247,7 @@
   static: |-
     <p data-sourcepos="3:1-3:5" dir="auto"><a href="/url%5Cbar*baz" title='foo"bar\baz'>foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url\bar*baz "foo"bar\baz"</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url%5Cbar*baz" title="foo&quot;bar\baz">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__012:
   canonical: |
@@ -2246,6 +2256,7 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="url">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="url">foo</a></p>
+    <pre>[foo]: url</pre>
 04_07__leaf_blocks__link_reference_definitions__013:
   canonical: |
     <p><a href="first">foo</a></p>
@@ -2253,12 +2264,15 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="first">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="first">foo</a></p>
+    <pre>[foo]: first</pre>
+    <pre>[foo]: second</pre>
 04_07__leaf_blocks__link_reference_definitions__014:
   canonical: |
     <p><a href="/url">Foo</a></p>
   static: |-
     <p data-sourcepos="3:1-3:5" dir="auto"><a href="/url">Foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">Foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__015:
   canonical: |
@@ -2266,18 +2280,20 @@
   static: |-
     <p data-sourcepos="3:1-3:8" dir="auto"><a href="/%CF%86%CE%BF%CF%85">αγω</a></p>
   wysiwyg: |-
+    <pre>[αγω]: /φου</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/%CF%86%CE%BF%CF%85">αγω</a></p>
 04_07__leaf_blocks__link_reference_definitions__016:
   canonical: ""
   static: ""
   wysiwyg: |-
-    <p></p>
+    <pre>[foo]: /url</pre>
 04_07__leaf_blocks__link_reference_definitions__017:
   canonical: |
     <p>bar</p>
   static: |-
     <p data-sourcepos="1:1-4:3" dir="auto">bar</p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <p>bar</p>
 04_07__leaf_blocks__link_reference_definitions__018:
   canonical: |
@@ -2292,6 +2308,7 @@
   static: |-
     <p data-sourcepos="1:1-2:10" dir="auto">"title" ok</p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <p>"title" ok</p>
 04_07__leaf_blocks__link_reference_definitions__020:
   canonical: |
@@ -2349,6 +2366,7 @@
     </blockquote>
   wysiwyg: |-
     <h1><a target="_blank" rel="noopener noreferrer nofollow" href="/url">Foo</a></h1>
+    <pre>[foo]: /url</pre>
     <blockquote multiline="false"><p>bar</p></blockquote>
 04_07__leaf_blocks__link_reference_definitions__024:
   canonical: |
@@ -2359,6 +2377,7 @@
     <a id="user-content-bar" class="anchor" href="#bar" aria-hidden="true"></a>bar</h1>
     <p data-sourcepos="4:1-4:5" dir="auto"><a href="/url">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <h1>bar</h1>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__025:
@@ -2369,6 +2388,7 @@
     <p data-sourcepos="1:1-3:5" dir="auto">===
     <a href="/url">foo</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url</pre>
     <p>===
     <a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a></p>
 04_07__leaf_blocks__link_reference_definitions__026:
@@ -2381,6 +2401,9 @@
     <a href="/bar-url" title="bar">bar</a>,
     <a href="/baz-url">baz</a></p>
   wysiwyg: |-
+    <pre>[foo]: /foo-url "foo"</pre>
+    <pre>[bar]: /bar-url "bar"</pre>
+    <pre>[baz]: /baz-url</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/foo-url" title="foo">foo</a>,
     <a target="_blank" rel="noopener noreferrer nofollow" href="/bar-url" title="bar">bar</a>,
     <a target="_blank" rel="noopener noreferrer nofollow" href="/baz-url">baz</a></p>
@@ -2395,12 +2418,12 @@
     </blockquote>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a></p>
-    <blockquote multiline="false"><p></p></blockquote>
+    <blockquote multiline="false"><pre>[foo]: /url</pre></blockquote>
 04_07__leaf_blocks__link_reference_definitions__028:
   canonical: ""
   static: ""
   wysiwyg: |-
-    <p></p>
+    <pre>[foo]: /url</pre>
 04_08__leaf_blocks__paragraphs__001:
   canonical: |
     <p>aaa</p>
@@ -4543,7 +4566,7 @@
     </li>
     </ul>
   wysiwyg: |-
-    <ul bullet="*"><li><p>a</p></li><li><p>b</p></li><li><p>d</p></li></ul>
+    <ul bullet="*"><li><p>a</p></li><li><p>b</p><pre>[ref]: /url</pre></li><li><p>d</p></li></ul>
 05_04__container_blocks__lists__018:
   canonical: |
     <ul>
@@ -4880,6 +4903,7 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="/bar*" title="ti*tle">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/bar*" title="ti*tle">foo</a></p>
+    <pre>[foo]: /bar* "ti*tle"</pre>
 06_02__inlines__backslash_escapes__013:
   canonical: |
     <pre><code class="language-foo+bar">foo
@@ -4969,6 +4993,7 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="/f%C3%B6%C3%B6" title="föö">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/f%C3%B6%C3%B6" title="föö">foo</a></p>
+    <pre>[foo]: /föö "föö"</pre>
 06_03__inlines__entity_and_numeric_character_references__010:
   canonical: |
     <pre><code class="language-föö">foo
@@ -6475,6 +6500,7 @@
     <p data-sourcepos="1:1-1:10" dir="auto"><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
+    <pre>[bar]: /url "title"</pre>
 06_07__inlines__links__044:
   canonical: |
     <p><a href="/uri">link [foo [bar]]</a></p>
@@ -6482,6 +6508,7 @@
     <p data-sourcepos="1:1-1:23" dir="auto"><a href="/uri">link [foo [bar]]</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">link [foo [bar]]</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__045:
   canonical: |
     <p><a href="/uri">link [bar</a></p>
@@ -6489,6 +6516,7 @@
     <p data-sourcepos="1:1-1:17" dir="auto"><a href="/uri">link [bar</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">link [bar</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__046:
   canonical: |
     <p><a href="/uri">link <em>foo <strong>bar</strong> <code>#</code></em></a></p>
@@ -6496,6 +6524,7 @@
     <p data-sourcepos="1:1-1:29" dir="auto"><a href="/uri">link <em>foo <strong>bar</strong> <code>#</code></em></a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">link <em>foo </em><strong><em>bar<code>#</code></em></strong></a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__047:
   canonical: |
     <p><a href="/uri"><img src="moon.jpg" alt="moon" /></a></p>
@@ -6503,6 +6532,7 @@
     <p data-sourcepos="1:1-1:24" dir="auto"><a href="/uri"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="moon" decoding="async" class="lazy" data-src="moon.jpg"></a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri"><img src="moon.jpg" alt="moon"></a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__048:
   canonical: |
     <p>[foo <a href="/uri">bar</a>]<a href="/uri">ref</a></p>
@@ -6510,6 +6540,7 @@
     <p data-sourcepos="1:1-1:22" dir="auto">[foo <a href="/uri">bar</a>]<a href="/uri">ref</a></p>
   wysiwyg: |-
     <p>[foo <a target="_blank" rel="noopener noreferrer nofollow" href="/uri">bar</a>]<a target="_blank" rel="noopener noreferrer nofollow" href="/uri">ref</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__049:
   canonical: |
     <p>[foo <em>bar <a href="/uri">baz</a></em>]<a href="/uri">ref</a></p>
@@ -6517,6 +6548,7 @@
     <p data-sourcepos="1:1-1:27" dir="auto">[foo <em>bar <a href="/uri">baz</a></em>]<a href="/uri">ref</a></p>
   wysiwyg: |-
     <p>[foo <em>bar </em><a target="_blank" rel="noopener noreferrer nofollow" href="/uri"><em>baz</em></a>]<a target="_blank" rel="noopener noreferrer nofollow" href="/uri">ref</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__050:
   canonical: |
     <p>*<a href="/uri">foo*</a></p>
@@ -6524,6 +6556,7 @@
     <p data-sourcepos="1:1-1:12" dir="auto">*<a href="/uri">foo*</a></p>
   wysiwyg: |-
     <p>*<a target="_blank" rel="noopener noreferrer nofollow" href="/uri">foo*</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__051:
   canonical: |
     <p><a href="/uri">foo *bar</a></p>
@@ -6531,6 +6564,7 @@
     <p data-sourcepos="1:1-1:15" dir="auto"><a href="/uri">foo *bar</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">foo *bar</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__052:
   canonical: |
     <p>[foo <bar attr="][ref]"></p>
@@ -6538,6 +6572,7 @@
     <p data-sourcepos="1:1-1:24" dir="auto">[foo </p>
   wysiwyg: |-
     <p>[foo </p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__053:
   canonical: |
     <p>[foo<code>][ref]</code></p>
@@ -6545,6 +6580,7 @@
     <p data-sourcepos="1:1-1:12" dir="auto">[foo<code>][ref]</code></p>
   wysiwyg: |-
     <p>[foo<code>][ref]</code></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__054:
   canonical: |
     <p>[foo<a href="http://example.com/?search=%5D%5Bref%5D">http://example.com/?search=][ref]</a></p>
@@ -6552,6 +6588,7 @@
     <p data-sourcepos="1:1-1:39" dir="auto">[foo<a href="http://example.com/?search=%5D%5Bref%5D" rel="nofollow noreferrer noopener" target="_blank">http://example.com/?search=][ref]</a></p>
   wysiwyg: |-
     <p>[foo<a target="_blank" rel="noopener noreferrer nofollow" href="http://example.com/?search=%5D%5Bref%5D">http://example.com/?search=][ref]</a></p>
+    <pre>[ref]: /uri</pre>
 06_07__inlines__links__055:
   canonical: |
     <p><a href="/url" title="title">foo</a></p>
@@ -6559,6 +6596,7 @@
     <p data-sourcepos="1:1-1:10" dir="auto"><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
+    <pre>[bar]: /url "title"</pre>
 06_07__inlines__links__056:
   canonical: |
     <p><a href="/url">Толпой</a> is a Russian word.</p>
@@ -6566,12 +6604,14 @@
     <p data-sourcepos="1:1-1:47" dir="auto"><a href="/url">Толпой</a> is a Russian word.</p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">Толпой</a> is a Russian word.</p>
+    <pre>[толпой]: /url</pre>
 06_07__inlines__links__057:
   canonical: |
     <p><a href="/url">Baz</a></p>
   static: |-
     <p data-sourcepos="4:1-4:14" dir="auto"><a href="/url">Baz</a></p>
   wysiwyg: |-
+    <pre>[foo bar]: /url</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">Baz</a></p>
 06_07__inlines__links__058:
   canonical: |
@@ -6580,6 +6620,7 @@
     <p data-sourcepos="1:1-1:11" dir="auto">[foo] <a href="/url" title="title">bar</a></p>
   wysiwyg: |-
     <p>[foo] <a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">bar</a></p>
+    <pre>[bar]: /url "title"</pre>
 06_07__inlines__links__059:
   canonical: |
     <p>[foo]
@@ -6590,12 +6631,15 @@
   wysiwyg: |-
     <p>[foo]
     <a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">bar</a></p>
+    <pre>[bar]: /url "title"</pre>
 06_07__inlines__links__060:
   canonical: |
     <p><a href="/url1">bar</a></p>
   static: |-
     <p data-sourcepos="5:1-5:10" dir="auto"><a href="/url1">bar</a></p>
   wysiwyg: |-
+    <pre>[foo]: /url1</pre>
+    <pre>[foo]: /url2</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url1">bar</a></p>
 06_07__inlines__links__061:
   canonical: |
@@ -6604,6 +6648,7 @@
     <p data-sourcepos="1:1-1:32" dir="auto">[bar][foo<span>!</span>]</p>
   wysiwyg: |-
     <p>[bar][foo!]</p>
+    <pre>[foo!]: /url</pre>
 06_07__inlines__links__062:
   canonical: |
     <p>[foo][ref[]</p>
@@ -6641,12 +6686,14 @@
     <p data-sourcepos="1:1-1:12" dir="auto"><a href="/uri">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">foo</a></p>
+    <pre>[ref\[]: /uri</pre>
 06_07__inlines__links__066:
   canonical: |
     <p><a href="/uri">bar\</a></p>
   static: |-
     <p data-sourcepos="3:1-3:7" dir="auto"><a href="/uri">bar\</a></p>
   wysiwyg: |-
+    <pre>[bar\\]: /uri</pre>
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/uri">bar\</a></p>
 06_07__inlines__links__067:
   canonical: |
@@ -6681,6 +6728,7 @@
     <p data-sourcepos="1:1-1:7" dir="auto"><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__070:
   canonical: |
     <p><a href="/url" title="title"><em>foo</em> bar</a></p>
@@ -6688,6 +6736,7 @@
     <p data-sourcepos="1:1-1:13" dir="auto"><a href="/url" title="title"><em>foo</em> bar</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title"><em>foo</em> bar</a></p>
+    <pre>[*foo* bar]: /url "title"</pre>
 06_07__inlines__links__071:
   canonical: |
     <p><a href="/url" title="title">Foo</a></p>
@@ -6695,6 +6744,7 @@
     <p data-sourcepos="1:1-1:7" dir="auto"><a href="/url" title="title">Foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">Foo</a></p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__072:
   canonical: |
     <p><a href="/url" title="title">foo</a>
@@ -6705,6 +6755,7 @@
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a>
     []</p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__073:
   canonical: |
     <p><a href="/url" title="title">foo</a></p>
@@ -6712,6 +6763,7 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__074:
   canonical: |
     <p><a href="/url" title="title"><em>foo</em> bar</a></p>
@@ -6719,6 +6771,7 @@
     <p data-sourcepos="1:1-1:11" dir="auto"><a href="/url" title="title"><em>foo</em> bar</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title"><em>foo</em> bar</a></p>
+    <pre>[*foo* bar]: /url "title"</pre>
 06_07__inlines__links__075:
   canonical: |
     <p>[<a href="/url" title="title"><em>foo</em> bar</a>]</p>
@@ -6726,6 +6779,7 @@
     <p data-sourcepos="1:1-1:13" dir="auto">[<a href="/url" title="title"><em>foo</em> bar</a>]</p>
   wysiwyg: |-
     <p>[<a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title"><em>foo</em> bar</a>]</p>
+    <pre>[*foo* bar]: /url "title"</pre>
 06_07__inlines__links__076:
   canonical: |
     <p>[[bar <a href="/url">foo</a></p>
@@ -6733,6 +6787,7 @@
     <p data-sourcepos="1:1-1:11" dir="auto">[[bar <a href="/url">foo</a></p>
   wysiwyg: |-
     <p>[[bar <a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a></p>
+    <pre>[foo]: /url</pre>
 06_07__inlines__links__077:
   canonical: |
     <p><a href="/url" title="title">Foo</a></p>
@@ -6740,6 +6795,7 @@
     <p data-sourcepos="1:1-1:5" dir="auto"><a href="/url" title="title">Foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">Foo</a></p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__078:
   canonical: |
     <p><a href="/url">foo</a> bar</p>
@@ -6747,6 +6803,7 @@
     <p data-sourcepos="1:1-1:9" dir="auto"><a href="/url">foo</a> bar</p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo</a> bar</p>
+    <pre>[foo]: /url</pre>
 06_07__inlines__links__079:
   canonical: |
     <p>[foo]</p>
@@ -6754,12 +6811,14 @@
     <p data-sourcepos="1:1-1:6" dir="auto">[foo]</p>
   wysiwyg: |-
     <p>[foo]</p>
+    <pre>[foo]: /url "title"</pre>
 06_07__inlines__links__080:
   canonical: |
     <p>*<a href="/url">foo*</a></p>
   static: |-
     <p data-sourcepos="3:1-3:7" dir="auto">*<a href="/url">foo*</a></p>
   wysiwyg: |-
+    <pre>[foo*]: /url</pre>
     <p>*<a target="_blank" rel="noopener noreferrer nofollow" href="/url">foo*</a></p>
 06_07__inlines__links__081:
   canonical: |
@@ -6768,6 +6827,8 @@
     <p data-sourcepos="1:1-1:10" dir="auto"><a href="/url2">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url2">foo</a></p>
+    <pre>[foo]: /url1</pre>
+    <pre>[bar]: /url2</pre>
 06_07__inlines__links__082:
   canonical: |
     <p><a href="/url1">foo</a></p>
@@ -6775,6 +6836,7 @@
     <p data-sourcepos="1:1-1:7" dir="auto"><a href="/url1">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url1">foo</a></p>
+    <pre>[foo]: /url1</pre>
 06_07__inlines__links__083:
   canonical: |
     <p><a href="">foo</a></p>
@@ -6782,6 +6844,7 @@
     <p data-sourcepos="1:1-1:7" dir="auto"><a href="">foo</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="">foo</a></p>
+    <pre>[foo]: /url1</pre>
 06_07__inlines__links__084:
   canonical: |
     <p><a href="/url1">foo</a>(not a link)</p>
@@ -6789,6 +6852,7 @@
     <p data-sourcepos="1:1-1:17" dir="auto"><a href="/url1">foo</a>(not a link)</p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url1">foo</a>(not a link)</p>
+    <pre>[foo]: /url1</pre>
 06_07__inlines__links__085:
   canonical: |
     <p>[foo]<a href="/url">bar</a></p>
@@ -6796,6 +6860,7 @@
     <p data-sourcepos="1:1-1:15" dir="auto">[foo]<a href="/url">bar</a></p>
   wysiwyg: |-
     <p>[foo]<a target="_blank" rel="noopener noreferrer nofollow" href="/url">bar</a></p>
+    <pre>[baz]: /url</pre>
 06_07__inlines__links__086:
   canonical: |
     <p><a href="/url2">foo</a><a href="/url1">baz</a></p>
@@ -6803,6 +6868,8 @@
     <p data-sourcepos="1:1-1:15" dir="auto"><a href="/url2">foo</a><a href="/url1">baz</a></p>
   wysiwyg: |-
     <p><a target="_blank" rel="noopener noreferrer nofollow" href="/url2">foo</a><a target="_blank" rel="noopener noreferrer nofollow" href="/url1">baz</a></p>
+    <pre>[baz]: /url1</pre>
+    <pre>[bar]: /url2</pre>
 06_07__inlines__links__087:
   canonical: |
     <p>[foo]<a href="/url1">bar</a></p>
@@ -6810,6 +6877,8 @@
     <p data-sourcepos="1:1-1:15" dir="auto">[foo]<a href="/url1">bar</a></p>
   wysiwyg: |-
     <p>[foo]<a target="_blank" rel="noopener noreferrer nofollow" href="/url1">bar</a></p>
+    <pre>[baz]: /url1</pre>
+    <pre>[foo]: /url2</pre>
 06_08__inlines__images__001:
   canonical: |
     <p><img src="/url" alt="foo" title="title" /></p>
@@ -6824,6 +6893,7 @@
     <p data-sourcepos="1:1-1:12" dir="auto"><a class="no-attachment-icon" href="train.jpg" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo bar" title="train &amp; tracks" decoding="async" class="lazy" data-src="train.jpg"></a></p>
   wysiwyg: |-
     <p><img src="train.jpg" alt="foo bar" title="train &amp; tracks"></p>
+    <pre>[foo *bar*]: train.jpg "train &amp; tracks"</pre>
 06_08__inlines__images__003:
   canonical: |
     <p><img src="/url2" alt="foo bar" /></p>
@@ -6845,6 +6915,7 @@
     <p data-sourcepos="1:1-1:14" dir="auto"><a class="no-attachment-icon" href="train.jpg" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo bar" title="train &amp; tracks" decoding="async" class="lazy" data-src="train.jpg"></a></p>
   wysiwyg: |-
     <p><img src="train.jpg" alt="foo bar" title="train &amp; tracks"></p>
+    <pre>[foo *bar*]: train.jpg "train &amp; tracks"</pre>
 06_08__inlines__images__006:
   canonical: |
     <p><img src="train.jpg" alt="foo bar" title="train &amp; tracks" /></p>
@@ -6852,6 +6923,7 @@
     <p data-sourcepos="1:1-1:20" dir="auto"><a class="no-attachment-icon" href="train.jpg" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo bar" title="train &amp; tracks" decoding="async" class="lazy" data-src="train.jpg"></a></p>
   wysiwyg: |-
     <p><img src="train.jpg" alt="foo bar" title="train &amp; tracks"></p>
+    <pre>[foobar]: train.jpg "train &amp; tracks"</pre>
 06_08__inlines__images__007:
   canonical: |
     <p><img src="train.jpg" alt="foo" /></p>
@@ -6887,6 +6959,7 @@
     <p data-sourcepos="1:1-1:11" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo"></p>
+    <pre>[bar]: /url</pre>
 06_08__inlines__images__012:
   canonical: |
     <p><img src="/url" alt="foo" /></p>
@@ -6894,6 +6967,7 @@
     <p data-sourcepos="1:1-1:11" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo"></p>
+    <pre>[bar]: /url</pre>
 06_08__inlines__images__013:
   canonical: |
     <p><img src="/url" alt="foo" title="title" /></p>
@@ -6901,6 +6975,7 @@
     <p data-sourcepos="1:1-1:8" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo" title="title"></p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__014:
   canonical: |
     <p><img src="/url" alt="foo bar" title="title" /></p>
@@ -6908,6 +6983,7 @@
     <p data-sourcepos="1:1-1:14" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo bar" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo bar" title="title"></p>
+    <pre>[*foo* bar]: /url "title"</pre>
 06_08__inlines__images__015:
   canonical: |
     <p><img src="/url" alt="Foo" title="title" /></p>
@@ -6915,6 +6991,7 @@
     <p data-sourcepos="1:1-1:8" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="Foo" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="Foo" title="title"></p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__016:
   canonical: |
     <p><img src="/url" alt="foo" title="title" />
@@ -6925,6 +7002,7 @@
   wysiwyg: |-
     <p><img src="/url" alt="foo" title="title">
     []</p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__017:
   canonical: |
     <p><img src="/url" alt="foo" title="title" /></p>
@@ -6932,6 +7010,7 @@
     <p data-sourcepos="1:1-1:6" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo" title="title"></p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__018:
   canonical: |
     <p><img src="/url" alt="foo bar" title="title" /></p>
@@ -6939,6 +7018,7 @@
     <p data-sourcepos="1:1-1:12" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="foo bar" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="foo bar" title="title"></p>
+    <pre>[*foo* bar]: /url "title"</pre>
 06_08__inlines__images__019:
   canonical: |
     <p>![[foo]]</p>
@@ -6956,6 +7036,7 @@
     <p data-sourcepos="1:1-1:6" dir="auto"><a class="no-attachment-icon" href="/url" target="_blank" rel="noopener noreferrer"><img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="Foo" title="title" decoding="async" class="lazy" data-src="/url"></a></p>
   wysiwyg: |-
     <p><img src="/url" alt="Foo" title="title"></p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__021:
   canonical: |
     <p>![foo]</p>
@@ -6963,6 +7044,7 @@
     <p data-sourcepos="1:1-1:7" dir="auto">![foo]</p>
   wysiwyg: |-
     <p>![foo]</p>
+    <pre>[foo]: /url "title"</pre>
 06_08__inlines__images__022:
   canonical: |
     <p>!<a href="/url" title="title">foo</a></p>
@@ -6970,6 +7052,7 @@
     <p data-sourcepos="1:1-1:27" dir="auto"><span>!</span><a href="/url" title="title">foo</a></p>
   wysiwyg: |-
     <p>!<a target="_blank" rel="noopener noreferrer nofollow" href="/url" title="title">foo</a></p>
+    <pre>[foo]: /url "title"</pre>
 06_09__inlines__autolinks__001:
   canonical: |
     <p><a href="http://foo.bar.baz">http://foo.bar.baz</a></p>
@@ -6990,7 +7073,7 @@
   static: |-
     <p data-sourcepos="1:1-1:24" dir="auto"><a href="irc://foo.bar:2233/baz">irc://foo.bar:2233/baz</a></p>
   wysiwyg: |-
-    <p><a target="_blank" rel="noopener noreferrer nofollow" href="irc://foo.bar:2233/baz">irc://foo.bar:2233/baz</a></p>
+    <p><a target="_blank" rel="noopener noreferrer nofollow">irc://foo.bar:2233/baz</a></p>
 06_09__inlines__autolinks__004:
   canonical: |
     <p><a href="MAILTO:FOO@BAR.BAZ">MAILTO:FOO@BAR.BAZ</a></p>
@@ -7004,14 +7087,14 @@
   static: |-
     <p data-sourcepos="1:1-1:9" dir="auto"><a href="a+b+c:d">a+b+c:d</a></p>
   wysiwyg: |-
-    <p><a target="_blank" rel="noopener noreferrer nofollow" href="a+b+c:d">a+b+c:d</a></p>
+    <p><a target="_blank" rel="noopener noreferrer nofollow">a+b+c:d</a></p>
 06_09__inlines__autolinks__006:
   canonical: |
     <p><a href="made-up-scheme://foo,bar">made-up-scheme://foo,bar</a></p>
   static: |-
     <p data-sourcepos="1:1-1:26" dir="auto"><a href="made-up-scheme://foo,bar">made-up-scheme://foo,bar</a></p>
   wysiwyg: |-
-    <p><a target="_blank" rel="noopener noreferrer nofollow" href="made-up-scheme://foo,bar">made-up-scheme://foo,bar</a></p>
+    <p><a target="_blank" rel="noopener noreferrer nofollow">made-up-scheme://foo,bar</a></p>
 06_09__inlines__autolinks__007:
   canonical: |
     <p><a href="http://../">http://../</a></p>
@@ -7025,7 +7108,7 @@
   static: |-
     <p data-sourcepos="1:1-1:20" dir="auto"><a href="localhost:5001/foo">localhost:5001/foo</a></p>
   wysiwyg: |-
-    <p><a target="_blank" rel="noopener noreferrer nofollow" href="localhost:5001/foo">localhost:5001/foo</a></p>
+    <p><a target="_blank" rel="noopener noreferrer nofollow">localhost:5001/foo</a></p>
 06_09__inlines__autolinks__009:
   canonical: |
     <p>&lt;http://foo.bar/baz bim&gt;</p>
@@ -7556,16 +7639,180 @@
   wysiwyg: |-
     <p>Multiple     spaces</p>
 07_01__gitlab_specific_markdown__footnotes__001:
-  canonical: ""
+  canonical: |
+    <p>
+    footnote reference tag
+    <sup>
+    <a href="#fn-fortytwo-42" id="fnref-fortytwo-42" data-footnote-ref>
+    1
+    </a>
+    </sup>
+    </p>
+    <section data-footnotes>
+    <ol>
+    <li id="fn-fortytwo-42">
+    <p>
+    footnote text
+    <a href="#fnref-fortytwo-42" data-footnote-backref>
+    </a>
+    </p>
+    </li>
+    </ol>
+    </section>
   static: |-
-    <p data-sourcepos="1:1-1:27" dir="auto">footnote reference tag <sup class="footnote-ref"><a href="#fn-1-9034" id="fnref-1-9034" data-footnote-ref>1</a></sup></p>
+    <p data-sourcepos="1:1-1:34" dir="auto">footnote reference tag <sup class="footnote-ref"><a href="#fn-fortytwo-42" id="fnref-fortytwo-42" data-footnote-ref>1</a></sup></p>
     <section data-footnotes class="footnotes">
     <ol>
-    <li id="fn-1-9034">
-    <p data-sourcepos="3:7-3:19">footnote text <a href="#fnref-1-9034" data-footnote-backref aria-label="Back to content" class="footnote-backref"><gl-emoji title="leftwards arrow with hook" data-name="leftwards_arrow_with_hook" data-unicode-version="1.1">↩</gl-emoji></a></p>
+    <li id="fn-fortytwo-42">
+    <p data-sourcepos="3:14-3:26">footnote text <a href="#fnref-fortytwo-42" data-footnote-backref aria-label="Back to content" class="footnote-backref"><gl-emoji title="leftwards arrow with hook" data-name="leftwards_arrow_with_hook" data-unicode-version="1.1">↩</gl-emoji></a></p>
     </li>
     </ol>
     </section>
   wysiwyg: |-
-    <p>footnote reference tag <sup identifier="1">1</sup></p>
+    <p>footnote reference tag <sup identifier="fortytwo">fortytwo</sup></p>
     <div node="footnoteDefinition(paragraph(&quot;footnote text&quot;))" htmlattributes="[object Object]"><p>footnote text</p></div>
+07_02__gitlab_specific_markdown__task_list_items__001:
+  canonical: |
+    <ul>
+    <li>
+    <task-button/>
+    <input type="checkbox" disabled/>
+    incomplete
+    </li>
+    </ul>
+  static: |-
+    <ul data-sourcepos="1:1-1:16" class="task-list" dir="auto">
+    <li data-sourcepos="1:1-1:16" class="task-list-item">
+    <task-button></task-button><input type="checkbox" class="task-list-item-checkbox" disabled> incomplete</li>
+    </ul>
+  wysiwyg: |-
+    <ul start="1" parens="false" data-type="taskList"><li data-checked="false" data-type="taskItem"><label><input type="checkbox"><span></span></label><div><p>incomplete</p></div></li></ul>
+07_02__gitlab_specific_markdown__task_list_items__002:
+  canonical: |
+    <ul>
+    <li>
+    <task-button/>
+    <input type="checkbox" checked disabled/>
+    completed
+    </li>
+    </ul>
+  static: |-
+    <ul data-sourcepos="1:1-1:15" class="task-list" dir="auto">
+    <li data-sourcepos="1:1-1:15" class="task-list-item">
+    <task-button></task-button><input type="checkbox" class="task-list-item-checkbox" checked disabled> completed</li>
+    </ul>
+  wysiwyg: |-
+    <ul start="1" parens="false" data-type="taskList"><li data-checked="true" data-type="taskItem"><label><input type="checkbox" checked="checked"><span></span></label><div><p>completed</p></div></li></ul>
+07_02__gitlab_specific_markdown__task_list_items__003:
+  canonical: |
+    <ul>
+    <li>
+    <task-button/>
+    <input type="checkbox" data-inapplicable disabled>
+    <s>
+    inapplicable
+    </s>
+    </li>
+    </ul>
+  static: |-
+    <ul data-sourcepos="1:1-1:18" class="task-list" dir="auto">
+    <li data-sourcepos="1:1-1:18" class="task-list-item inapplicable">
+    <task-button></task-button><input type="checkbox" class="task-list-item-checkbox" data-inapplicable disabled> <s>inapplicable</s>
+    </li>
+    </ul>
+07_02__gitlab_specific_markdown__task_list_items__004:
+  canonical: |
+    <ul>
+    <li>
+    <p>
+    <task-button/>
+    <input type="checkbox" data-inapplicable disabled>
+    <s>
+    inapplicable
+    </s>
+    </p>
+    <p>
+    text in loose list
+    </p>
+    </li>
+    </ul>
+  static: |-
+    <ul data-sourcepos="1:1-3:20" class="task-list" dir="auto">
+    <li data-sourcepos="1:1-3:20" class="task-list-item inapplicable">
+    <p data-sourcepos="1:3-1:18"><task-button></task-button><input type="checkbox" class="task-list-item-checkbox" data-inapplicable disabled> <s>inapplicable</s></p>
+    <p data-sourcepos="3:3-3:20">text in loose list</p>
+    </li>
+    </ul>
+07_03__gitlab_specific_markdown__front_matter__001:
+  canonical: |
+    <pre>
+    <code>
+    title: YAML front matter
+    </code>
+    </pre>
+  static: |-
+    <div class="gl-relative markdown-code-block js-markdown-code">
+    <pre data-sourcepos="1:1-3:3" class="code highlight js-syntax-highlight language-yaml" lang="yaml" data-lang-params="frontmatter" v-pre="true"><code><span id="LC1" class="line" lang="yaml"><span class="na">title</span><span class="pi">:</span> <span class="s">YAML front matter</span></span></code></pre>
+    <copy-code></copy-code>
+    </div>
+  wysiwyg: |-
+    <pre language="yaml" class="content-editor-code-block undefined code highlight" isfrontmatter="true"><code>title: YAML front matter</code></pre>
+07_03__gitlab_specific_markdown__front_matter__002:
+  canonical: |
+    <pre>
+    <code>
+    title: TOML front matter
+    </code>
+    </pre>
+  static: |-
+    <div class="gl-relative markdown-code-block js-markdown-code">
+    <pre data-sourcepos="1:1-3:3" class="code highlight js-syntax-highlight language-toml" lang="toml" data-lang-params="frontmatter" v-pre="true"><code><span id="LC1" class="line" lang="toml"><span class="err">title:</span> <span class="err">TOML</span> <span class="err">front</span> <span class="err">matter</span></span></code></pre>
+    <copy-code></copy-code>
+    </div>
+  wysiwyg: |-
+    <pre language="toml" class="content-editor-code-block undefined code highlight" isfrontmatter="true"><code>title: TOML front matter</code></pre>
+07_03__gitlab_specific_markdown__front_matter__003:
+  canonical: |
+    <pre>
+    <code>
+    {
+      "title": "JSON front matter"
+    }
+    </code>
+    </pre>
+  static: |-
+    <div class="gl-relative markdown-code-block js-markdown-code">
+    <pre data-sourcepos="1:1-5:3" class="code highlight js-syntax-highlight language-json" lang="json" data-lang-params="frontmatter" v-pre="true"><code><span id="LC1" class="line" lang="json"><span class="p">{</span></span>
+    <span id="LC2" class="line" lang="json"><span class="w">  </span><span class="nl">"title"</span><span class="p">:</span><span class="w"> </span><span class="s2">"JSON front matter"</span></span>
+    <span id="LC3" class="line" lang="json"><span class="p">}</span></span></code></pre>
+    <copy-code></copy-code>
+    </div>
+  wysiwyg: |-
+    <pre language="json" class="content-editor-code-block undefined code highlight" isfrontmatter="true"><code>{
+      "title": "JSON front matter"
+    }</code></pre>
+07_03__gitlab_specific_markdown__front_matter__004:
+  canonical: |
+    <p>text</p>
+    <hr>
+    <h2>title: YAML front matter</h2>
+  static: |-
+    <p data-sourcepos="1:1-1:4" dir="auto">text</p>
+    <hr data-sourcepos="3:1-3:3">
+    <h2 data-sourcepos="4:1-5:3" dir="auto">
+    <a id="user-content-title-yaml-front-matter" class="anchor" href="#title-yaml-front-matter" aria-hidden="true"></a>title: YAML front matter</h2>
+  wysiwyg: |-
+    <p>text</p>
+    <hr>
+    <h2>title: YAML front matter</h2>
+07_03__gitlab_specific_markdown__front_matter__005:
+  canonical: |
+    <hr>
+    <h2>title: YAML front matter</h2>
+  static: |-
+    <hr data-sourcepos="1:2-1:4">
+    <h2 data-sourcepos="2:1-3:3" dir="auto">
+    <a id="user-content-title-yaml-front-matter" class="anchor" href="#title-yaml-front-matter" aria-hidden="true"></a>title: YAML front matter</h2>
+  wysiwyg: |-
+    <hr>
+    <h2>title: YAML front matter</h2>
diff --git a/glfm_specification/example_snapshots/markdown.yml b/glfm_specification/example_snapshots/markdown.yml
index de0e66f7e08..c875beb77f5 100644
--- a/glfm_specification/example_snapshots/markdown.yml
+++ b/glfm_specification/example_snapshots/markdown.yml
@@ -2190,6 +2190,40 @@
 06_15__inlines__textual_content__003: |
   Multiple     spaces
 07_01__gitlab_specific_markdown__footnotes__001: |
-  footnote reference tag [^1]
+  footnote reference tag [^fortytwo]
+
+  [^fortytwo]: footnote text
+07_02__gitlab_specific_markdown__task_list_items__001: |
+  - [ ] incomplete
+07_02__gitlab_specific_markdown__task_list_items__002: |
+  - [x] completed
+07_02__gitlab_specific_markdown__task_list_items__003: |
+  - [~] inapplicable
+07_02__gitlab_specific_markdown__task_list_items__004: |
+  - [~] inapplicable
+
+    text in loose list
+07_03__gitlab_specific_markdown__front_matter__001: |
+  ---
+  title: YAML front matter
+  ---
+07_03__gitlab_specific_markdown__front_matter__002: |
+  +++
+  title: TOML front matter
+  +++
+07_03__gitlab_specific_markdown__front_matter__003: |
+  ;;;
+  {
+    "title": "JSON front matter"
+  }
+  ;;;
+07_03__gitlab_specific_markdown__front_matter__004: |
+  text
 
-  [^1]: footnote text
+  ---
+  title: YAML front matter
+  ---
+07_03__gitlab_specific_markdown__front_matter__005: |2
+   ---
+  title: YAML front matter
+  ---
diff --git a/glfm_specification/example_snapshots/prosemirror_json.yml b/glfm_specification/example_snapshots/prosemirror_json.yml
index 0a8c15e9650..9f0d462aed3 100644
--- a/glfm_specification/example_snapshots/prosemirror_json.yml
+++ b/glfm_specification/example_snapshots/prosemirror_json.yml
@@ -1702,12 +1702,11 @@
     "type": "doc",
     "content": [
       {
-        "type": "horizontalRule"
-      },
-      {
-        "type": "heading",
+        "type": "frontmatter",
         "attrs": {
-          "level": 2
+          "language": "yaml",
+          "class": "code highlight",
+          "isFrontmatter": true
         },
         "content": [
           {
@@ -1759,10 +1758,12 @@
     "type": "doc",
     "content": [
       {
-        "type": "horizontalRule"
-      },
-      {
-        "type": "horizontalRule"
+        "type": "frontmatter",
+        "attrs": {
+          "language": "yaml",
+          "class": "code highlight",
+          "isFrontmatter": true
+        }
       }
     ]
   }
@@ -3149,7 +3150,8 @@
                       "target": "_blank",
                       "class": null,
                       "title": null,
-                      "canonicalSrc": null
+                      "canonicalSrc": "bar",
+                      "isReference": false
                     }
                   }
                 ],
@@ -3234,7 +3236,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": false
                 }
               }
             ],
@@ -3752,7 +3755,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": false
                 }
               }
             ],
@@ -3884,6 +3888,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -3896,7 +3914,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -3911,6 +3930,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "the title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"the title\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -3923,7 +3956,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "the title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -3938,6 +3972,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo*bar\\]",
+          "url": "my_(url)",
+          "title": "title (with parens)"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo*bar\\]]: my_(url) \"title (with parens)\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -3950,7 +3998,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title (with parens)",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo*bar\\]",
+                  "isReference": true
                 }
               }
             ],
@@ -3965,6 +4014,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo bar",
+          "url": "my url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo bar]: my url \"title\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -3977,7 +4040,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo bar",
+                  "isReference": true
                 }
               }
             ],
@@ -3992,6 +4056,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "\ntitle\nline1\nline2\n"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"\ntitle\nline1\nline2\n\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4004,7 +4082,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "\ntitle\nline1\nline2\n",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4052,6 +4131,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4064,7 +4157,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4103,6 +4197,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: "
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4115,7 +4223,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4154,6 +4263,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url\\bar*baz",
+          "title": "foo\"bar\\baz"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url\\bar*baz \"foo\"bar\\baz\""
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4166,7 +4289,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "foo\"bar\\baz",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4193,13 +4317,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: url"
+          }
+        ]
       }
     ]
   }
@@ -4220,13 +4359,42 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "first",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: first"
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "second",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: second"
+          }
+        ]
       }
     ]
   }
@@ -4235,6 +4403,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4247,7 +4429,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4262,6 +4445,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "αγω",
+          "url": "/φου",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[αγω]: /φου"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4274,7 +4471,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "αγω",
+                  "isReference": true
                 }
               }
             ],
@@ -4289,7 +4487,18 @@
     "type": "doc",
     "content": [
       {
-        "type": "paragraph"
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
       }
     ]
   }
@@ -4298,6 +4507,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4328,6 +4551,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4438,7 +4675,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4447,6 +4685,20 @@
         ]
       },
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "blockquote",
         "attrs": {
           "multiline": false
@@ -4470,6 +4722,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "heading",
         "attrs": {
           "level": 1
@@ -4494,7 +4760,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4509,6 +4776,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4525,7 +4806,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4540,6 +4822,48 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/foo-url",
+          "title": "foo"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /foo-url \"foo\""
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/bar-url",
+          "title": "bar"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /bar-url \"bar\""
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "baz",
+          "url": "/baz-url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[baz]: /baz-url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -4552,7 +4876,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "foo",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4572,7 +4897,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "bar",
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
@@ -4592,7 +4918,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "baz",
+                  "isReference": true
                 }
               }
             ],
@@ -4619,7 +4946,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -4634,7 +4962,18 @@
         },
         "content": [
           {
-            "type": "paragraph"
+            "type": "referenceDefinition",
+            "attrs": {
+              "identifier": "foo",
+              "url": "/url",
+              "title": null
+            },
+            "content": [
+              {
+                "type": "text",
+                "text": "[foo]: /url"
+              }
+            ]
           }
         ]
       }
@@ -4645,7 +4984,18 @@
     "type": "doc",
     "content": [
       {
-        "type": "paragraph"
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
       }
     ]
   }
@@ -9572,6 +9922,20 @@
                     "text": "b"
                   }
                 ]
+              },
+              {
+                "type": "referenceDefinition",
+                "attrs": {
+                  "identifier": "ref",
+                  "url": "/url",
+                  "title": null
+                },
+                "content": [
+                  {
+                    "type": "text",
+                    "text": "[ref]: /url"
+                  }
+                ]
               }
             ]
           },
@@ -10346,7 +10710,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com?find=%5C*",
+                  "isReference": false
                 }
               }
             ],
@@ -10382,7 +10747,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "ti*tle",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/bar*",
+                  "isReference": false
                 }
               }
             ],
@@ -10409,13 +10775,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "ti*tle",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/bar*",
+          "title": "ti*tle"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /bar* \"ti*tle\""
+          }
+        ]
       }
     ]
   }
@@ -10554,7 +10935,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "föö",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/f%C3%B6%C3%B6",
+                  "isReference": false
                 }
               }
             ],
@@ -10581,13 +10963,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "föö",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/föö",
+          "title": "föö"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /föö \"föö\""
+          }
+        ]
       }
     ]
   }
@@ -11101,7 +11498,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "`",
+                  "isReference": false
                 }
               }
             ],
@@ -11152,7 +11550,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar.%60baz",
+                  "isReference": false
                 }
               }
             ],
@@ -12308,7 +12707,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               },
               {
@@ -12778,7 +13178,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               },
               {
@@ -12847,7 +13248,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               },
               {
@@ -13206,7 +13608,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               },
               {
@@ -14112,7 +14515,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               }
             ],
@@ -14143,7 +14547,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               }
             ],
@@ -14171,7 +14576,8 @@
               "alt": null,
               "title": "*",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": false
             }
           }
         ]
@@ -14293,7 +14699,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar/?q=**",
+                  "isReference": false
                 }
               }
             ],
@@ -14324,7 +14731,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar/?q=__",
+                  "isReference": false
                 }
               }
             ],
@@ -14399,7 +14807,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -14426,7 +14835,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -14453,7 +14863,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "",
+                  "isReference": false
                 }
               }
             ],
@@ -14480,7 +14891,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "",
+                  "isReference": false
                 }
               }
             ],
@@ -14522,7 +14934,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/my%20uri",
+                  "isReference": false
                 }
               }
             ],
@@ -14579,7 +14992,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "b)c",
+                  "isReference": false
                 }
               }
             ],
@@ -14645,7 +15059,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "(foo)",
+                  "isReference": false
                 }
               }
             ],
@@ -14672,7 +15087,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo(and(bar))",
+                  "isReference": false
                 }
               }
             ],
@@ -14699,7 +15115,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo(and(bar)",
+                  "isReference": false
                 }
               }
             ],
@@ -14726,7 +15143,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo(and(bar)",
+                  "isReference": false
                 }
               }
             ],
@@ -14753,7 +15171,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo):",
+                  "isReference": false
                 }
               }
             ],
@@ -14780,7 +15199,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "#fragment",
+                  "isReference": false
                 }
               }
             ],
@@ -14801,7 +15221,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com#fragment",
+                  "isReference": false
                 }
               }
             ],
@@ -14822,7 +15243,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com?foo=3#frag",
+                  "isReference": false
                 }
               }
             ],
@@ -14849,7 +15271,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo%5Cbar",
+                  "isReference": false
                 }
               }
             ],
@@ -14876,7 +15299,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo%20b%C3%A4",
+                  "isReference": false
                 }
               }
             ],
@@ -14903,7 +15327,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "%22title%22",
+                  "isReference": false
                 }
               }
             ],
@@ -14930,7 +15355,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               }
             ],
@@ -14957,7 +15383,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title \"\"",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               }
             ],
@@ -14984,7 +15411,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url%C2%A0%22title%22",
+                  "isReference": false
                 }
               }
             ],
@@ -15026,7 +15454,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title \"and\" title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/url",
+                  "isReference": false
                 }
               }
             ],
@@ -15053,7 +15482,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15095,7 +15525,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15141,7 +15572,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15168,7 +15600,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15195,7 +15628,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15211,7 +15645,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               },
               {
@@ -15230,7 +15665,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               },
               {
@@ -15252,7 +15688,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               },
               {
@@ -15285,7 +15722,8 @@
               "alt": "moon",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "moon.jpg",
+              "isReference": false
             },
             "marks": [
               {
@@ -15295,7 +15733,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ]
@@ -15325,7 +15764,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15369,7 +15809,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               },
               {
@@ -15409,7 +15850,8 @@
               "alt": "[foo](uri2)",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "uri3",
+              "isReference": false
             }
           }
         ]
@@ -15437,7 +15879,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15464,7 +15907,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "baz*",
+                  "isReference": false
                 }
               }
             ],
@@ -15558,7 +16002,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com/?search=%5D(uri)",
+                  "isReference": false
                 }
               }
             ],
@@ -15585,13 +16030,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -15612,13 +16072,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "link [foo [bar]]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15639,13 +16114,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "link [bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15666,7 +16156,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
@@ -15682,7 +16173,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               },
               {
@@ -15701,7 +16193,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               },
               {
@@ -15723,7 +16216,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               },
               {
@@ -15739,6 +16233,20 @@
             "text": "#"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15756,7 +16264,8 @@
               "alt": "moon",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "moon.jpg",
+              "isReference": false
             },
             "marks": [
               {
@@ -15766,12 +16275,27 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ]
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15796,7 +16320,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "/uri",
+                  "isReference": false
                 }
               }
             ],
@@ -15816,13 +16341,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "ref"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15856,7 +16396,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               },
               {
@@ -15879,13 +16420,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "ref"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15910,13 +16466,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo*"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15937,13 +16508,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo *bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15959,6 +16545,20 @@
             "text": "[foo "
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -15983,6 +16583,20 @@
             "text": "][ref]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -16007,13 +16621,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com/?search=%5D%5Bref%5D",
+                  "isReference": false
                 }
               }
             ],
             "text": "http://example.com/?search=][ref]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -16034,13 +16663,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16061,7 +16705,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "толпой",
+                  "isReference": true
                 }
               }
             ],
@@ -16072,6 +16717,20 @@
             "text": " is a Russian word."
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "толпой",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[толпой]: /url"
+          }
+        ]
       }
     ]
   }
@@ -16080,6 +16739,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo bar",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo bar]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -16092,7 +16765,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo bar",
+                  "isReference": true
                 }
               }
             ],
@@ -16123,13 +16797,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
             "text": "bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16154,13 +16843,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
             "text": "bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16169,6 +16873,34 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url1"
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url2",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url2"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -16181,7 +16913,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -16203,6 +16936,20 @@
             "text": "[bar][foo!]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo!",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo!]: /url"
+          }
+        ]
       }
     ]
   }
@@ -16295,13 +17042,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "ref\\[",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "ref\\[",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[ref\\[]: /uri"
+          }
+        ]
       }
     ]
   }
@@ -16310,6 +17072,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar\\\\",
+          "url": "/uri",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar\\\\]: /uri"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -16322,7 +17098,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar\\\\",
+                  "isReference": true
                 }
               }
             ],
@@ -16397,13 +17174,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16424,7 +17216,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               },
               {
@@ -16443,13 +17236,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               }
             ],
             "text": " bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "*foo* bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[*foo* bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16470,13 +17278,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "Foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16497,7 +17320,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -16508,6 +17332,20 @@
             "text": "\n[]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16528,13 +17366,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16555,7 +17408,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               },
               {
@@ -16574,13 +17428,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               }
             ],
             "text": " bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "*foo* bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[*foo* bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16605,7 +17474,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               },
               {
@@ -16624,7 +17494,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "*foo* bar",
+                  "isReference": true
                 }
               }
             ],
@@ -16635,6 +17506,20 @@
             "text": "]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "*foo* bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[*foo* bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16659,13 +17544,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
       }
     ]
   }
@@ -16686,13 +17586,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "Foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16713,7 +17628,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -16724,6 +17640,20 @@
             "text": " bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url"
+          }
+        ]
       }
     ]
   }
@@ -16739,6 +17669,20 @@
             "text": "[foo]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -16747,6 +17691,20 @@
     "type": "doc",
     "content": [
       {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo*",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo*]: /url"
+          }
+        ]
+      },
+      {
         "type": "paragraph",
         "content": [
           {
@@ -16763,7 +17721,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo*",
+                  "isReference": true
                 }
               }
             ],
@@ -16790,13 +17749,42 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url1"
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url2",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url2"
+          }
+        ]
       }
     ]
   }
@@ -16817,13 +17805,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url1"
+          }
+        ]
       }
     ]
   }
@@ -16844,13 +17847,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "",
+                  "isReference": false
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url1"
+          }
+        ]
       }
     ]
   }
@@ -16871,7 +17889,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
@@ -16882,6 +17901,20 @@
             "text": "(not a link)"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url1"
+          }
+        ]
       }
     ]
   }
@@ -16906,13 +17939,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "baz",
+                  "isReference": true
                 }
               }
             ],
             "text": "bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "baz",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[baz]: /url"
+          }
+        ]
       }
     ]
   }
@@ -16933,7 +17981,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "bar",
+                  "isReference": true
                 }
               }
             ],
@@ -16949,13 +17998,42 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "baz",
+                  "isReference": true
                 }
               }
             ],
             "text": "baz"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "baz",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[baz]: /url1"
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url2",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url2"
+          }
+        ]
       }
     ]
   }
@@ -16980,13 +18058,42 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "baz",
+                  "isReference": true
                 }
               }
             ],
             "text": "bar"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "baz",
+          "url": "/url1",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[baz]: /url1"
+          }
+        ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url2",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url2"
+          }
+        ]
       }
     ]
   }
@@ -17004,7 +18111,8 @@
               "alt": "foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "/url",
+              "isReference": false
             }
           }
         ]
@@ -17025,10 +18133,25 @@
               "alt": "foo bar",
               "title": "train & tracks",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo *bar*",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo *bar*",
+          "url": "train.jpg",
+          "title": "train & tracks"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo *bar*]: train.jpg \"train & tracks\""
+          }
+        ]
       }
     ]
   }
@@ -17046,7 +18169,8 @@
               "alt": "foo bar",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "/url2",
+              "isReference": false
             }
           }
         ]
@@ -17067,7 +18191,8 @@
               "alt": "foo bar",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "/url2",
+              "isReference": false
             }
           }
         ]
@@ -17088,10 +18213,25 @@
               "alt": "foo bar",
               "title": "train & tracks",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo *bar*",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo *bar*",
+          "url": "train.jpg",
+          "title": "train & tracks"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo *bar*]: train.jpg \"train & tracks\""
+          }
+        ]
       }
     ]
   }
@@ -17109,10 +18249,25 @@
               "alt": "foo bar",
               "title": "train & tracks",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foobar",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foobar",
+          "url": "train.jpg",
+          "title": "train & tracks"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foobar]: train.jpg \"train & tracks\""
+          }
+        ]
       }
     ]
   }
@@ -17130,7 +18285,8 @@
               "alt": "foo",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "train.jpg",
+              "isReference": false
             }
           }
         ]
@@ -17155,7 +18311,8 @@
               "alt": "foo bar",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "/path/to/train.jpg",
+              "isReference": false
             }
           }
         ]
@@ -17176,7 +18333,8 @@
               "alt": "foo",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "url",
+              "isReference": false
             }
           }
         ]
@@ -17197,7 +18355,8 @@
               "alt": "",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "/url",
+              "isReference": false
             }
           }
         ]
@@ -17218,10 +18377,25 @@
               "alt": "foo",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "bar",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url"
+          }
+        ]
       }
     ]
   }
@@ -17239,10 +18413,25 @@
               "alt": "foo",
               "title": null,
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "bar",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "bar",
+          "url": "/url",
+          "title": null
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[bar]: /url"
+          }
+        ]
       }
     ]
   }
@@ -17260,10 +18449,25 @@
               "alt": "foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17281,10 +18485,25 @@
               "alt": "foo bar",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "*foo* bar",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "*foo* bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[*foo* bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17302,10 +18521,25 @@
               "alt": "Foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17323,7 +18557,8 @@
               "alt": "foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": true
             }
           },
           {
@@ -17331,6 +18566,20 @@
             "text": "\n[]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17348,10 +18597,25 @@
               "alt": "foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17369,10 +18633,25 @@
               "alt": "foo bar",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "*foo* bar",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "*foo* bar",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[*foo* bar]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17414,10 +18693,25 @@
               "alt": "Foo",
               "title": "title",
               "uploading": false,
-              "canonicalSrc": null
+              "canonicalSrc": "foo",
+              "isReference": true
             }
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17433,6 +18727,20 @@
             "text": "![foo]"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17457,13 +18765,28 @@
                   "target": "_blank",
                   "class": null,
                   "title": "title",
-                  "canonicalSrc": null
+                  "canonicalSrc": "foo",
+                  "isReference": true
                 }
               }
             ],
             "text": "foo"
           }
         ]
+      },
+      {
+        "type": "referenceDefinition",
+        "attrs": {
+          "identifier": "foo",
+          "url": "/url",
+          "title": "title"
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "[foo]: /url \"title\""
+          }
+        ]
       }
     ]
   }
@@ -17484,7 +18807,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar.baz",
+                  "isReference": false
                 }
               }
             ],
@@ -17511,7 +18835,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar.baz/test?q=hello&id=22&boolean",
+                  "isReference": false
                 }
               }
             ],
@@ -17534,11 +18859,12 @@
               {
                 "type": "link",
                 "attrs": {
-                  "href": "irc://foo.bar:2233/baz",
+                  "href": null,
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": null,
+                  "isReference": false
                 }
               }
             ],
@@ -17565,7 +18891,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "MAILTO:FOO@BAR.BAZ",
+                  "isReference": false
                 }
               }
             ],
@@ -17588,11 +18915,12 @@
               {
                 "type": "link",
                 "attrs": {
-                  "href": "a+b+c:d",
+                  "href": null,
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": null,
+                  "isReference": false
                 }
               }
             ],
@@ -17615,11 +18943,12 @@
               {
                 "type": "link",
                 "attrs": {
-                  "href": "made-up-scheme://foo,bar",
+                  "href": null,
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": null,
+                  "isReference": false
                 }
               }
             ],
@@ -17646,7 +18975,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://../",
+                  "isReference": false
                 }
               }
             ],
@@ -17669,11 +18999,12 @@
               {
                 "type": "link",
                 "attrs": {
-                  "href": "localhost:5001/foo",
+                  "href": null,
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": null,
+                  "isReference": false
                 }
               }
             ],
@@ -17704,7 +19035,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar/baz",
+                  "isReference": false
                 }
               }
             ],
@@ -17735,7 +19067,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com/%5C%5B%5C",
+                  "isReference": false
                 }
               }
             ],
@@ -17762,7 +19095,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:foo@bar.example.com",
+                  "isReference": false
                 }
               }
             ],
@@ -17789,7 +19123,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:foo+special@Bar.baz-bar0.com",
+                  "isReference": false
                 }
               }
             ],
@@ -17820,7 +19155,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:foo+@bar.example.com",
+                  "isReference": false
                 }
               }
             ],
@@ -17870,7 +19206,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://foo.bar",
+                  "isReference": false
                 }
               }
             ],
@@ -17931,7 +19268,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://example.com",
+                  "isReference": false
                 }
               }
             ],
@@ -17958,7 +19296,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:foo@bar.example.com",
+                  "isReference": false
                 }
               }
             ],
@@ -17985,7 +19324,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.commonmark.org",
+                  "isReference": false
                 }
               }
             ],
@@ -18016,7 +19356,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.commonmark.org/help",
+                  "isReference": false
                 }
               }
             ],
@@ -18051,7 +19392,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.commonmark.org",
+                  "isReference": false
                 }
               }
             ],
@@ -18080,7 +19422,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.commonmark.org/a.b",
+                  "isReference": false
                 }
               }
             ],
@@ -18111,7 +19454,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=Markup+(business)",
+                  "isReference": false
                 }
               }
             ],
@@ -18132,7 +19476,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=Markup+(business)",
+                  "isReference": false
                 }
               }
             ],
@@ -18161,7 +19506,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=Markup+(business)",
+                  "isReference": false
                 }
               }
             ],
@@ -18190,7 +19536,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=Markup+(business)",
+                  "isReference": false
                 }
               }
             ],
@@ -18217,7 +19564,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=(business))+ok",
+                  "isReference": false
                 }
               }
             ],
@@ -18244,7 +19592,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=commonmark&hl=en",
+                  "isReference": false
                 }
               }
             ],
@@ -18265,7 +19614,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.google.com/search?q=commonmark",
+                  "isReference": false
                 }
               }
             ],
@@ -18296,7 +19646,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://www.commonmark.org/he",
+                  "isReference": false
                 }
               }
             ],
@@ -18327,7 +19678,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "http://commonmark.org",
+                  "isReference": false
                 }
               }
             ],
@@ -18352,7 +19704,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "https://encrypted.google.com/search?q=Markup+(business)",
+                  "isReference": false
                 }
               }
             ],
@@ -18392,7 +19745,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:foo@bar.baz",
+                  "isReference": false
                 }
               }
             ],
@@ -18423,7 +19777,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:hello+xyz@mail.example",
+                  "isReference": false
                 }
               }
             ],
@@ -18454,7 +19809,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:a.b-c_d@a.b",
+                  "isReference": false
                 }
               }
             ],
@@ -18475,7 +19831,8 @@
                   "target": "_blank",
                   "class": null,
                   "title": null,
-                  "canonicalSrc": null
+                  "canonicalSrc": "mailto:a.b-c_d@a.b",
+                  "isReference": false
                 }
               }
             ],
@@ -19218,8 +20575,8 @@
           {
             "type": "footnoteReference",
             "attrs": {
-              "identifier": "1",
-              "label": "1"
+              "identifier": "fortytwo",
+              "label": "fortytwo"
             }
           }
         ]
@@ -19227,8 +20584,8 @@
       {
         "type": "footnoteDefinition",
         "attrs": {
-          "identifier": "1",
-          "label": "1"
+          "identifier": "fortytwo",
+          "label": "fortytwo"
         },
         "content": [
           {
@@ -19244,3 +20601,184 @@
       }
     ]
   }
+07_02__gitlab_specific_markdown__task_list_items__001: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "taskList",
+        "attrs": {
+          "numeric": false,
+          "start": 1,
+          "parens": false
+        },
+        "content": [
+          {
+            "type": "taskItem",
+            "attrs": {
+              "checked": false
+            },
+            "content": [
+              {
+                "type": "paragraph",
+                "content": [
+                  {
+                    "type": "text",
+                    "text": "incomplete"
+                  }
+                ]
+              }
+            ]
+          }
+        ]
+      }
+    ]
+  }
+07_02__gitlab_specific_markdown__task_list_items__002: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "taskList",
+        "attrs": {
+          "numeric": false,
+          "start": 1,
+          "parens": false
+        },
+        "content": [
+          {
+            "type": "taskItem",
+            "attrs": {
+              "checked": true
+            },
+            "content": [
+              {
+                "type": "paragraph",
+                "content": [
+                  {
+                    "type": "text",
+                    "text": "completed"
+                  }
+                ]
+              }
+            ]
+          }
+        ]
+      }
+    ]
+  }
+07_02__gitlab_specific_markdown__task_list_items__003: |-
+  Inapplicable task list items not yet implemented for WYSYWIG
+07_02__gitlab_specific_markdown__task_list_items__004: |-
+  Inapplicable task list items not yet implemented for WYSYWIG
+07_03__gitlab_specific_markdown__front_matter__001: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "frontmatter",
+        "attrs": {
+          "language": "yaml",
+          "class": "code highlight",
+          "isFrontmatter": true
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "title: YAML front matter"
+          }
+        ]
+      }
+    ]
+  }
+07_03__gitlab_specific_markdown__front_matter__002: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "frontmatter",
+        "attrs": {
+          "language": "toml",
+          "class": "code highlight",
+          "isFrontmatter": true
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "title: TOML front matter"
+          }
+        ]
+      }
+    ]
+  }
+07_03__gitlab_specific_markdown__front_matter__003: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "frontmatter",
+        "attrs": {
+          "language": "json",
+          "class": "code highlight",
+          "isFrontmatter": true
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "{\n  \"title\": \"JSON front matter\"\n}"
+          }
+        ]
+      }
+    ]
+  }
+07_03__gitlab_specific_markdown__front_matter__004: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "paragraph",
+        "content": [
+          {
+            "type": "text",
+            "text": "text"
+          }
+        ]
+      },
+      {
+        "type": "horizontalRule"
+      },
+      {
+        "type": "heading",
+        "attrs": {
+          "level": 2
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "title: YAML front matter"
+          }
+        ]
+      }
+    ]
+  }
+07_03__gitlab_specific_markdown__front_matter__005: |-
+  {
+    "type": "doc",
+    "content": [
+      {
+        "type": "horizontalRule"
+      },
+      {
+        "type": "heading",
+        "attrs": {
+          "level": 2
+        },
+        "content": [
+          {
+            "type": "text",
+            "text": "title: YAML front matter"
+          }
+        ]
+      }
+    ]
+  }
diff --git a/glfm_specification/input/gitlab_flavored_markdown/glfm_canonical_examples.txt b/glfm_specification/input/gitlab_flavored_markdown/glfm_canonical_examples.txt
index e4d01b4a813..332b311dff2 100644
--- a/glfm_specification/input/gitlab_flavored_markdown/glfm_canonical_examples.txt
+++ b/glfm_specification/input/gitlab_flavored_markdown/glfm_canonical_examples.txt
@@ -14,7 +14,188 @@ See
 [the footnotes section of the user-facing documentation for GitLab Flavored Markdown](https://docs.gitlab.com/ee/user/markdown.html#footnotes).
 
 ```````````````````````````````` example gitlab footnote
-footnote reference tag [^1]
+footnote reference tag [^fortytwo]
 
-[^1]: footnote text
+[^fortytwo]: footnote text
+.
+<p>
+footnote reference tag
+<sup>
+<a href="#fn-fortytwo-42" id="fnref-fortytwo-42" data-footnote-ref>
+1
+</a>
+</sup>
+</p>
+<section data-footnotes>
+<ol>
+<li id="fn-fortytwo-42">
+<p>
+footnote text
+<a href="#fnref-fortytwo-42" data-footnote-backref>
+</a>
+</p>
+</li>
+</ol>
+</section>
+````````````````````````````````
+
+## Task list items
+
+See
+[Task lists](https://docs.gitlab.com/ee/user/markdown.html#task-lists) in the GitLab Flavored Markdown documentation.
+
+Task list items (checkboxes) are defined as a GitHub Flavored Markdown extension in a section above.
+GitLab extends the behavior of task list items to support additional features.
+Some of these features are in-progress, and should not yet be considered part of the official
+GitLab Flavored Markdown specification.
+
+Some of the behavior of task list items is implemented as client-side JavaScript/CSS.
+
+The following are some basic examples; more examples may be added in the future.
+
+Incomplete task:
+
+```````````````````````````````` example gitlab tasklist
+- [ ] incomplete
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" disabled/>
+incomplete
+</li>
+</ul>
+````````````````````````````````
+
+Completed task:
+
+```````````````````````````````` example gitlab tasklist
+- [x] completed
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" checked disabled/>
+completed
+</li>
+</ul>
+````````````````````````````````
+
+Inapplicable task:
+
+```````````````````````````````` example gitlab tasklist
+- [~] inapplicable
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" data-inapplicable disabled>
+<s>
+inapplicable
+</s>
+</li>
+</ul>
+````````````````````````````````
+
+Inapplicable task in a "loose" list. Note that the `<del>` tag is not applied to the
+loose text; it has strikethrough applied with CSS.
+
+```````````````````````````````` example gitlab tasklist
+- [~] inapplicable
+
+  text in loose list
+.
+<ul>
+<li>
+<p>
+<task-button/>
+<input type="checkbox" data-inapplicable disabled>
+<s>
+inapplicable
+</s>
+</p>
+<p>
+text in loose list
+</p>
+</li>
+</ul>
+````````````````````````````````
+
+## Front matter
+
+See
+[Front matter](https://docs.gitlab.com/ee/user/markdown.html#front-matter) in the GitLab Flavored Markdown documentation.
+
+Front matter is metadata included at the beginning of a Markdown document, preceding the content.
+This data can be used by static site generators like Jekyll, Hugo, and many other applications.
+
+YAML front matter:
+
+```````````````````````````````` example gitlab frontmatter
+---
+title: YAML front matter
+---
+.
+<pre>
+<code>
+title: YAML front matter
+</code>
+</pre>
+````````````````````````````````
+
+TOML front matter:
+
+```````````````````````````````` example gitlab frontmatter
++++
+title: TOML front matter
++++
+.
+<pre>
+<code>
+title: TOML front matter
+</code>
+</pre>
+````````````````````````````````
+
+JSON front matter:
+
+```````````````````````````````` example gitlab frontmatter
+;;;
+{
+  "title": "JSON front matter"
+}
+;;;
+.
+<pre>
+<code>
+{
+  "title": "JSON front matter"
+}
+</code>
+</pre>
+````````````````````````````````
+
+Front matter blocks should be inserted at the top of the document:
+
+```````````````````````````````` example gitlab frontmatter
+text
+
+---
+title: YAML front matter
+---
+.
+<p>text</p>
+<hr>
+<h2>title: YAML front matter</h2>
+````````````````````````````````
+
+Front matter block delimiters shouldn’t be preceded by space characters:
+
+```````````````````````````````` example gitlab frontmatter
+ ---
+title: YAML front matter
+---
+.
+<hr>
+<h2>title: YAML front matter</h2>
 ````````````````````````````````
diff --git a/glfm_specification/input/gitlab_flavored_markdown/glfm_example_status.yml b/glfm_specification/input/gitlab_flavored_markdown/glfm_example_status.yml
index b09a092c02a..3881819e38a 100644
--- a/glfm_specification/input/gitlab_flavored_markdown/glfm_example_status.yml
+++ b/glfm_specification/input/gitlab_flavored_markdown/glfm_example_status.yml
@@ -12,3 +12,15 @@
   skip_running_snapshot_static_html_tests: false # NOT YET SUPPORTED
   skip_running_snapshot_wysiwyg_html_tests: false
   skip_running_snapshot_prosemirror_json_tests: false
+07_02__gitlab_specific_markdown__task_list_items__003:
+  skip_update_example_snapshot_html_wysiwyg: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_update_example_snapshot_prosemirror_json: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_conformance_wysiwyg_tests: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_snapshot_wysiwyg_html_tests: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_snapshot_prosemirror_json_tests: Inapplicable task list items not yet implemented for WYSYWIG
+07_02__gitlab_specific_markdown__task_list_items__004:
+  skip_update_example_snapshot_html_wysiwyg: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_update_example_snapshot_prosemirror_json: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_conformance_wysiwyg_tests: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_snapshot_wysiwyg_html_tests: Inapplicable task list items not yet implemented for WYSYWIG
+  skip_running_snapshot_prosemirror_json_tests: Inapplicable task list items not yet implemented for WYSYWIG
diff --git a/glfm_specification/output/spec.txt b/glfm_specification/output/spec.txt
index c81daf7f689..32cb6a0594e 100644
--- a/glfm_specification/output/spec.txt
+++ b/glfm_specification/output/spec.txt
@@ -9616,9 +9616,190 @@ See
 [the footnotes section of the user-facing documentation for GitLab Flavored Markdown](https://docs.gitlab.com/ee/user/markdown.html#footnotes).
 
 ```````````````````````````````` example gitlab footnote
-footnote reference tag [^1]
+footnote reference tag [^fortytwo]
 
-[^1]: footnote text
+[^fortytwo]: footnote text
+.
+<p>
+footnote reference tag
+<sup>
+<a href="#fn-fortytwo-42" id="fnref-fortytwo-42" data-footnote-ref>
+1
+</a>
+</sup>
+</p>
+<section data-footnotes>
+<ol>
+<li id="fn-fortytwo-42">
+<p>
+footnote text
+<a href="#fnref-fortytwo-42" data-footnote-backref>
+</a>
+</p>
+</li>
+</ol>
+</section>
+````````````````````````````````
+
+## Task list items
+
+See
+[Task lists](https://docs.gitlab.com/ee/user/markdown.html#task-lists) in the GitLab Flavored Markdown documentation.
+
+Task list items (checkboxes) are defined as a GitHub Flavored Markdown extension in a section above.
+GitLab extends the behavior of task list items to support additional features.
+Some of these features are in-progress, and should not yet be considered part of the official
+GitLab Flavored Markdown specification.
+
+Some of the behavior of task list items is implemented as client-side JavaScript/CSS.
+
+The following are some basic examples; more examples may be added in the future.
+
+Incomplete task:
+
+```````````````````````````````` example gitlab tasklist
+- [ ] incomplete
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" disabled/>
+incomplete
+</li>
+</ul>
+````````````````````````````````
+
+Completed task:
+
+```````````````````````````````` example gitlab tasklist
+- [x] completed
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" checked disabled/>
+completed
+</li>
+</ul>
+````````````````````````````````
+
+Inapplicable task:
+
+```````````````````````````````` example gitlab tasklist
+- [~] inapplicable
+.
+<ul>
+<li>
+<task-button/>
+<input type="checkbox" data-inapplicable disabled>
+<s>
+inapplicable
+</s>
+</li>
+</ul>
+````````````````````````````````
+
+Inapplicable task in a "loose" list. Note that the `<del>` tag is not applied to the
+loose text; it has strikethrough applied with CSS.
+
+```````````````````````````````` example gitlab tasklist
+- [~] inapplicable
+
+  text in loose list
+.
+<ul>
+<li>
+<p>
+<task-button/>
+<input type="checkbox" data-inapplicable disabled>
+<s>
+inapplicable
+</s>
+</p>
+<p>
+text in loose list
+</p>
+</li>
+</ul>
+````````````````````````````````
+
+## Front matter
+
+See
+[Front matter](https://docs.gitlab.com/ee/user/markdown.html#front-matter) in the GitLab Flavored Markdown documentation.
+
+Front matter is metadata included at the beginning of a Markdown document, preceding the content.
+This data can be used by static site generators like Jekyll, Hugo, and many other applications.
+
+YAML front matter:
+
+```````````````````````````````` example gitlab frontmatter
+---
+title: YAML front matter
+---
+.
+<pre>
+<code>
+title: YAML front matter
+</code>
+</pre>
+````````````````````````````````
+
+TOML front matter:
+
+```````````````````````````````` example gitlab frontmatter
++++
+title: TOML front matter
++++
+.
+<pre>
+<code>
+title: TOML front matter
+</code>
+</pre>
+````````````````````````````````
+
+JSON front matter:
+
+```````````````````````````````` example gitlab frontmatter
+;;;
+{
+  "title": "JSON front matter"
+}
+;;;
+.
+<pre>
+<code>
+{
+  "title": "JSON front matter"
+}
+</code>
+</pre>
+````````````````````````````````
+
+Front matter blocks should be inserted at the top of the document:
+
+```````````````````````````````` example gitlab frontmatter
+text
+
+---
+title: YAML front matter
+---
+.
+<p>text</p>
+<hr>
+<h2>title: YAML front matter</h2>
+````````````````````````````````
+
+Front matter block delimiters shouldn’t be preceded by space characters:
+
+```````````````````````````````` example gitlab frontmatter
+ ---
+title: YAML front matter
+---
+.
+<hr>
+<h2>title: YAML front matter</h2>
 ````````````````````````````````
 
 <!-- END TESTS -->