diff --git a/source b/source
index 8793f1bf3f8..5392d04c451 100644
--- a/source
+++ b/source
@@ -88241,6 +88241,9 @@ new PaymentRequest(…); // Allowed to use
 
   <div w-nodev>
 
+  <p><code>Document</code> objects have a <dfn export>navigation counter</dfn> (an integer) which
+  is initially zero.</p>
+
   <p>To <dfn>traverse the history</dfn> to a <span>session history entry</span> <var>entry</var>,
   with an optional <span>history handling behavior</span> <dfn
   data-x="traverse-history-hh"><var>historyHandling</var></dfn> (default "<code
@@ -88376,6 +88379,8 @@ new PaymentRequest(&hellip;); // Allowed to use
 
        <li><p>Set <var>newDocument</var>'s <span>page showing</span> flag to true.</p></li>
 
+       <li><p>Increment <var>newDocument</var>'s <span>navigation counter</span>.</p></li>
+
        <li>
         <p>Run any <dfn>session history document visibility change steps</dfn> for
         <var>newDocument</var> that are defined by <span>other applicable specifications</span>.</p>