Now there are two official branches, the stable 3.3.5 and the newest 6.x.
The 4.3.4 branch was not stable nor new, but the deletion of it caused malcontent and led to the creation of a separated repository at GitLab which aims to continue the development of the 4.3.4 game version. Behind it there are some TrinityCore DB developers:
https://gitlab.com/trinitycore/TrinityCore_434/
The DB releases for 4.3.4 will be published in another repository located at GitHub: