diff --git a/index.bs b/index.bs
index 9890191b..83b128a3 100644
--- a/index.bs
+++ b/index.bs
@@ -4219,6 +4219,8 @@ manner suiting the user.</p>
    <li>
     <p>Apply the terms of the CSS specifications to |regionNode| within the following constraints,
     thus obtaining a CSS box |box| positioned relative to an initial containing block:</p>
+    <p class="note">The CSS specification application may make changes to a number of variables,
+    including |lineHeight|.</p>
     <ol>
      <li><p>No style sheets are associated with |regionNode|. (The regionNodes are subsequently
      restyled using style sheets after their boxes are generated, as described below.)</p></li>
diff --git a/index.html b/index.html
index d041b479..91ed9ddd 100644
--- a/index.html
+++ b/index.html
@@ -4520,6 +4520,8 @@ <h3 class="heading settled algorithm" data-algorithm="Processing model" data-lev
       <li>
        <p>Apply the terms of the CSS specifications to <var>regionNode</var> within the following constraints,
     thus obtaining a CSS box <var>box</var> positioned relative to an initial containing block:</p>
+       <p class="note" role="note">The CSS specification application may make changes to a number of variables,
+    including <var>lineHeight</var>.</p>
        <ol>
         <li>
          <p>No style sheets are associated with <var>regionNode</var>. (The regionNodes are subsequently