diff --git a/source b/source
index 6aee3ee4989..2eaae3bda2f 100644
--- a/source
+++ b/source
@@ -68530,6 +68530,14 @@ Demos:
     </ul>
    </dd>
 
+   <dt><dfn noexport><code data-x="selector-autofill">:autofill</code></dfn></dt>
+   <dd>
+    <p>The <code data-x="selector-autofill">:autofill</code> <span>pseudo-class</span> must match
+    <code>input</code> elements which have been auto-completed by the user-agent. This pseudo-class
+    must stop matching if the user edits the auto-completed field. User-agents may support
+    <code>:-webkit-autofill</code> as a legacy alias for compatibility reasons.
+   </dd>
+
    <dt><dfn noexport><code data-x="selector-read-only">:read-only</code></dfn></dt>
    <dt><dfn noexport><code data-x="selector-read-write">:read-write</code></dfn></dt>
    <dd>