* I'm planning to enable it for toolkit/ and browser/ soon. This is
likely to be a phased roll-out.
* Due to the way our import system works (Cu.import and also xul/html
files including multiple js files), detecting all the globals has
been quite complicated. We're getting there, but it isn't perfect
yet, but we've already been finding bugs and dead code, so the
benefits are real.
* The devmo page lists hints for working with no-undef
<https://developer.mozilla.org/docs/ESLint#no-undef>. These should
hopefully get simpler over time.
If there's any questions or comments, please stop by #eslint on irc.