I've gathered together what's left of it and invest in that. Through much trial and error, I've figured out the bits which work in both Chrome and the rest of the 25 years worth of historic browsers and write for that.
Sounds interesting. Care to publish your results (yes I know caniuse however I'm more after a core set of browser APIs/features defining a "real" long-term standard)? Btw I myself have also put quite some effort in distilling a HTML DTD grammar from WHATWG/W3C materials [1], defending it in conferences, etc.
