chromium/third_party/blink/web_tests/css3/selectors3/xml/css3-modsel-19b.xml

<?xml-stylesheet href="css3-modsel-19b.css" type="text/css"?>
<test>
<p xmlns="http://www.w3.org/1999/xhtml"><button>Activating (e.g. holding the mouse button down on) this button should make it go green.</button></p>
</test>