user/test/com/google/gwt/resources/converter/undefined-constants.gss

.foo {
  display: none;
  color: jfk_my_stuff;
  background-color: jfk_123_asd;
}

.cellTableHeader {
  padding: header_vertical_padding header_horizontal_padding;
}

@def TOP top;

.foo {
  background-image: url(data:image/svg+xml;base64,PD94basdfasdfasdf);
  background: -webkit-gradient(linear, left TOP, right TOP, from(rgba(255, 255, 255, 0)), to(#fff));
}