Hmm, so what is the status of this W3C draft[1] (which they say specifically does not imply endorsement), if the W3C is putting a test for it in one of their test suites? Or do Chrome/Chrome devs get commit bits? Or maybe one of the purposes of this is to serve as a way for browsers to coordinate on implementations even before it's become a standard? (It's obviously a way to coordinate on things that are a standard).

1: https://www.w3.org/TR/css-typed-om-1/