I spend a fair amount of time contributing to Mozilla and other browser vendors and (hopefully) improving HTML accessibility implementations in browsers by filing bugs, working on the HTML spec at the W3C, discussing issues with browser acc engineers etc. As part of this work I recently developed tests and tested the interoperability of HTML5 accessibility implementation requirements in all of the major browsers (Firefox, Chrome, IE and Safari). This was a time consuming and arduous task i undertook in my own time, because I want accessibility implementations to work in browsers. It is with regret that I read the decision makers at Mozilla see the work myself and many others do at the W3C as having little value to Mozilla.
NOTE: I have not said #Mozilla don't care about accessibility, but questioned the simplistic narrative of HTML at the W3C = ALL BAD and HTML