chromium/src/third_party/blink/web_tests/css3/selectors3/xml/css3-modsel-121.css

@namespace html url(http://www.w3.org/1999/xhtml);
@namespace a url(http://www.example.org/a);
@namespace b url(http://www.example.org/b);
div.stub > *|* { color : red ; display : block ;
                 margin-bottom : 1em }
div.stub > *|*:not(a|*) { color : green  }
div.stub v { color : green }