diff --git a/source b/source
index 9d6d0e035de..bc429e58bd0 100644
--- a/source
+++ b/source
@@ -42745,6 +42745,25 @@ interface <dfn>HTMLTableCellElement</dfn> : <span>HTMLElement</span> {
 
    </dd>
 
+   <dt><dfn data-x="category-autocapitalize">Autocapitalize-inheriting elements</dfn></dt>
+
+   <dd>
+
+    <p>Denotes elements that inherit the <code data-x="attr-autocapitalize">autocapitalize</code>
+    attribute from their <span>form owner</span>.</p>
+
+    <!-- when updating this also update the category index -->
+    <ul class="brief category-list">
+     <li><code>button</code></li>
+     <li><code>fieldset</code></li>
+     <li><code>input</code></li>
+     <li><code>output</code></li>
+     <li><code>select</code></li>
+     <li><code>textarea</code></li>
+    </ul>
+
+   </dd>
+
   </dl>
 
   <p>Some elements, not all of them <span data-x="form-associated element">form-associated</span>,
@@ -43380,8 +43399,8 @@ interface <dfn>HTMLLabelElement</dfn> : <span>HTMLElement</span> {
    <dd><span>Flow content</span>.</dd>
    <dd><span>Phrasing content</span>.</dd>
    <dd>If the <code data-x="attr-input-type">type</code> attribute is <em>not</em> in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span>Interactive content</span>.</dd>
-   <dd>If the <code data-x="attr-input-type">type</code> attribute is <em>not</em> in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, and <span data-x="category-reset">resettable</span> <span>form-associated element</span>.</dd>
-   <dd>If the <code data-x="attr-input-type">type</code> attribute is in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span data-x="category-listed">Listed</span>, <span data-x="category-submit">submittable</span>, and <span data-x="category-reset">resettable</span> <span>form-associated element</span>.</dd>
+   <dd>If the <code data-x="attr-input-type">type</code> attribute is <em>not</em> in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, <span data-x="category-reset">resettable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
+   <dd>If the <code data-x="attr-input-type">type</code> attribute is in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span data-x="category-listed">Listed</span>, <span data-x="category-submit">submittable</span>, <span data-x="category-reset">resettable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd>If the <code data-x="attr-input-type">type</code> attribute is <em>not</em> in the <span data-x="attr-input-type-hidden">Hidden</span> state: <span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>phrasing content</span> is expected.</dd>
@@ -49547,7 +49566,7 @@ You cannot submit this form when the field is incorrect.</samp></pre>
    <dd><span>Flow content</span>.</dd>
    <dd><span>Phrasing content</span>.</dd>
    <dd><span>Interactive content</span>.</dd>
-   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, and <span data-x="category-submit">submittable</span> <span>form-associated element</span>.</dd>
+   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd><span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>phrasing content</span> is expected.</dd>
@@ -49744,7 +49763,7 @@ interface <dfn>HTMLButtonElement</dfn> : <span>HTMLElement</span> {
    <dd><span>Flow content</span>.</dd>
    <dd><span>Phrasing content</span>.</dd>
    <dd><span>Interactive content</span>.</dd>
-   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, and <span data-x="category-reset">resettable</span> <span>form-associated element</span>.</dd>
+   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, <span data-x="category-reset">resettable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd><span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>phrasing content</span> is expected.</dd>
@@ -50756,7 +50775,7 @@ interface <dfn>HTMLOptionElement</dfn> : <span>HTMLElement</span> {
    <dd><span>Flow content</span>.</dd>
    <dd><span>Phrasing content</span>.</dd>
    <dd><span>Interactive content</span>.</dd>
-   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, and <span data-x="category-reset">resettable</span> <span>form-associated element</span>.</dd>
+   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-submit">submittable</span>, <span data-x="category-reset">resettable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd><span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>phrasing content</span> is expected.</dd>
@@ -51262,7 +51281,7 @@ Daddy">&lt;/textarea></pre>
    <dt><span data-x="concept-element-categories">Categories</span>:</dt>
    <dd><span>Flow content</span>.</dd>
    <dd><span>Phrasing content</span>.</dd>
-   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, and <span data-x="category-reset">resettable</span> <span>form-associated element</span>.</dd>
+   <dd><span data-x="category-listed">Listed</span>, <span data-x="category-label">labelable</span>, <span data-x="category-reset">resettable</span>, and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd><span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>phrasing content</span> is expected.</dd>
@@ -52009,7 +52028,7 @@ out of 233&#x2009;257&#x2009;824 bytes available&lt;/meter>&lt;/p></pre>
    <dt><span data-x="concept-element-categories">Categories</span>:</dt>
    <dd><span>Flow content</span>.</dd>
    <dd><span>Sectioning root</span>.</dd>
-   <dd><span data-x="category-listed">Listed</span> <span>form-associated element</span>.</dd>
+   <dd><span data-x="category-listed">Listed</span> and <span data-x="category-autocapitalize">autocapitalize-inheriting</span> <span>form-associated element</span>.</dd>
    <dd><span>Palpable content</span>.</dd>
    <dt><span data-x="concept-element-contexts">Contexts in which this element can be used</span>:</dt>
    <dd>Where <span>flow content</span> is expected.</dd>
@@ -74362,7 +74381,8 @@ body { display:none }
   data-x="editing host">editing host</span> to control autocapitalization behavior for the hosted
   editable region, on an <code>input</code> or <code>textarea</code> element to control the behavior
   for inputting text into that element, or on a <code>form</code> element to control the default
-  behavior for that form's <code>input</code> and <code>textarea</code> elements.</p>
+  behavior for all <span data-x="category-autocapitalize">autocapitalize-inheriting elements</span>
+  associated with the <code>form</code> element.
 
   <p>The <code data-x="attr-autocapitalize">autocapitalize</code> attribute never causes
   autocapitalization to be enabled for <code>input</code> elements whose <code
@@ -74459,8 +74479,9 @@ body { display:none }
    present on <var>element</var>, and its value is not the empty string, return the state of the
    attribute.</p></li>
 
-   <li><p>If <var>element</var> is an <code>input</code> or <code>textarea</code> element and has a
-   non-null <span>form owner</span>, return the <span>own autocapitalization hint</span> of
+   <li><p>If <var>element</var> is an <span
+   data-x="category-autocapitalize">autocapitalize-inheriting element</span> and has a non-null
+   <span>form owner</span>, return the <span>own autocapitalization hint</span> of
    <var>element</var>'s <span>form owner</span>.</p></li>
 
    <li><p>Return <span data-x="autocap-hint-default">default</span>.</p></li>
@@ -117558,6 +117579,18 @@ interface <dfn>External</dfn> {
      <td>
       &mdash;
 
+    <tr>
+     <td> <span data-x="category-autocapitalize">Autocapitalize-inheriting elements</span>
+     <td>
+      <code>button</code>;
+      <code>fieldset</code>;
+      <code>input</code>;
+      <code>output</code>;
+      <code>select</code>;
+      <code>textarea</code>
+     <td>
+      &mdash;
+
     <tr>
      <td> <span data-x="category-label">Labelable elements</span>
      <td>