chromium/src/third_party/blink/web_tests/css3/selectors3/xml/css3-modsel-137.css

@namespace a url(http://www.example.org/a);
@namespace b url(http://www.example.org/b);
@namespace html url(http://www.w3.org/1999/xhtml);
*|q, *|r { display : block ; margin-bottom : 1em }
*|q { background-color : red }
div.stub *|*:not([|title]) { background-color : lime }