isomorphic encoded userAgent

Author: sadym-chromium

fetch.bs

@@ -5898,8 +5898,10 @@ run these steps:
      <a>WebDriver BiDi emulated User-Agent</a> with <var>httpRequest</var>'s
      <a for=request>client</a>.
 
-     <li><p>If <var>userAgent</var> is null, then set <var>userAgent</var> to
-     <a>default `<code>User-Agent</code>` value</a>.
+     <li><p>If <var>userAgent</var> is not null, then set <var>userAgent</var> to
+     <a>isomorphic encoded</a> <var>userAgent</var>.
+
+     <li><p>Otherwise, set <var>userAgent</var> to <a>default `<code>User-Agent</code>` value</a>.
 
      <li><p><a for="header list">Append</a> (`<code>User-Agent</code>`, <var>userAgent</var>) to
      <var>httpRequest</var>'s <a for=request>header list</a>.