E2E is our main focus at the moment - sorry for missing the question; we must have missed it. There's nothing on github as the E2E stuff is all hosted on https://matrix.org/git/olm. The FAQ is old - we have finished the 1:1 ratchet and group ratchet and almost all the key distribution stuff. Currently wiring it into all the SDKs and checking it works and then getting it audited. We should be ready to yell about it in N weeks where 2<N<5.
I tried asking in the group chat as well but nobody seemed to know.
[0]: https://matrix.org/docs/guides/faq.html#how-secure-is-this