I asked this in the forums a few years ago, back then the most vocal core devs were against it. But git.minetest.net
would be such an awesome thing.
They could run an own GitLab instance there and move main development off of the Microsoft service. For backwards compatibility they could mirror the repost to MS GitLab like they do with GitLab.com right now.
In the long term even the CDB could be hosted there.
But two chances to cleanly do the move were missed. First was the release of so-called “Minetest 5.0”, the first release after the 0.x era and the second chance was when lots of other FOSS projects left GitHub when Microsoft bought it.