chromium/third_party/blink/web_tests/css3/selectors3/xml/css3-modsel-20.xml

<?xml-stylesheet href="css3-modsel-20.css" type="text/css"?>
<test>
<p xmlns="http://www.w3.org/1999/xhtml">The background color of <a href="#foo">anchors</a>
  in this page should turn <a href="#foo">to green</a> when they have the
  <a href="#foo">focus</a>.</p>
</test>