diff --git a/source b/source
index 17ac4d82005..758e834d236 100644
--- a/source
+++ b/source
@@ -91772,11 +91772,19 @@ dictionary <dfn dictionary>WindowPostMessageOptions</dfn> : <span>StructuredSeri
    </li>
   </ol>
 
-  <p>A <span>navigable</span> is <dfn>script-closable</dfn> if its <span data-x="nav-bc">active
-  browsing context</span> is an <span>auxiliary browsing context</span> that was created by a
-  script (as opposed to by an action of the user), or if it is a <span>top-level traversable</span>
-  whose <span data-x="tn-session-history-entries">session history entries</span>'s <span
-  data-x="list size">size</span> is 1.</p>
+  <p>A <span>navigable</span> is <dfn>script-closable</dfn> if it is a
+  <span>top-level traversable</span>, and any of the following is true:</p>
+  <ul>
+    <li>it <span>is created by web content</span>; or</li>
+    <li>its <span data-x="tn-session-history-entries">session history entries</span>'s
+    <span data-x="list size">size</span> is 1.</li>
+  </ul>
+
+  <!--
+    https://source.chromium.org/chromium/chromium/src/+/b20d6a654f6891ed49373d9f535d8618ded1e2e2
+    The session history check is a special case for one-off windows that need to open other windows
+    and then dispose of themselves. This use case might not be necessary anymore.
+  -->
 
   <p>The <dfn attribute for="Window"><code data-x="dom-window-closed">closed</code></dfn> getter
   steps are to return true if <span>this</span>'s <span data-x="window bc">browsing context</span>
@@ -98494,6 +98502,8 @@ interface <dfn interface>NotRestoredReasons</dfn> {
     <p>See the <a href="#page-visibility">page visibility</a> section for the requirements on this
     item.</p>
    </li>
+
+   <li><p>An <dfn>is created by web content</dfn> boolean, initially false.</p></li>
   </ul>
 
   <p>To get the <dfn data-x="nav-traversable" export for="navigable">traversable navigable</dfn> of
@@ -99480,6 +99490,9 @@ interface <dfn interface>NotRestoredReasons</dfn> {
        contexts flag</span> is set, then all the flags that are set in <var>sandboxingFlagSet</var>
        must be set in <var>chosen</var>'s <span data-x="nav-bc">active browsing context</span>'s
        <span>popup sandboxing flag set</span>.</p></li>
+
+       <li><p>Set <var>targetNavigable</var>'s <span>is created by web content</span> to true.</p>
+      </li>
       </ol>
 
       <p class="note">If the newly created <span>navigable</span> <var>chosen</var> is immediately