Web Browser roadmap for HTML5 features?

I've been watching the caniuse.com site for a while now, and at one extreme we have Firefox releasing a new browser once/week (okay, slight exaggeration), and at the other extreme the Android list of 2.1/2.2/2.3/3.0/4.0/4.1/4.2 never changes. There is still nothing in the "Near future" or "Farther future" rows. There are a number of HTML5 technologies not implemented even in 4.2, and I'm wondering when there is a new version coming, and what we can expect it to support. (EDIT: I'm looking for links to official announcements, developer blogs, etc. or a confident "nobody knows"; not speculation.) (E.g. http://caniuse.com/eventsource ) (BTW, the StackOverflow Android tag seemed to suggest this was the best place to ask this kind of question. But if another site is better please let me know.)