Georg and I have finally filed the full set of tags for the ff38-esr work, based on the developer documentation review and the Mozilla bugtracker review. Everything should be in this tag now: https://trac.torproject.org/projects/tor/query?status=!closed&keywords=~...
I also broke out the set of things we really need to have ready for 5.0a3 on June 30th: https://trac.torproject.org/projects/tor/query?status=!closed&keywords=~...
Those tickets represent major proxy safety audit work, patch rebase work, build system bugs, and major functionality bugs. Basically those bugs are blockers for us deploying a safe, usable, functioning TBB 5.0a3 based on Firefox 38.
The set of bugs that really want to get fixed in some kind of alpha release before 5.0-stable are: https://trac.torproject.org/projects/tor/query?status=!closed&keywords=~...
We should aim to get those bugs fixed for 5.0a3, but if a lot of them still end up remaining after 5.0a3, we'll want to consider either another alpha sometime in July, or do a "soft launch" release of TBB 5.0 before August 11th, so we don't have to autoupgrade 4.5.x users to it right away.
The code freeze for 5.0a3 will be June 23, though we can probably slip a couple things to as late as June 25. In other words, we've got about 2 weeks left to get through that essential list and make a dent in tbb-5.0a-highrisk.