I have changes now for the Lilypond and LaTeX bundle that I'd like to share. Are the TM2 "Managed Bundles" at https://github.com/avian the correct place to target?
I have received information from Michael Sheets, who's TextMate bundles maintainer, that this is the correct place to fork from if you want to provide changes for TM2 bundles.
All the best for the upcoming new year,