The functional pseudo-class like :matches() with 0 specificity
is now named :where().
https://github.com/w3c/csswg-drafts/issues/2143#issuecomment-432303830
Blink currently has the pseudo-class implemented as :is.
When we change the name to :where, we can contribute tests to WPT.
Comment 1 by ericwilligers@chromium.org
, Oct 23Status: Started (was: Untriaged)