Manifest Version 3

Does Firefox support Manifest V3?
If not, what is the current estimated timeline?

No, it is still in development and there is no timeline announced so far. As soon as a timeline exists I’d expect it to be announced on https://blog.mozilla.org/addons/

Honestly, let’s hope they don’t for a while. MV3 is horrible to work with.

I think we can all agree that mv3 sucks and it sucks that Google are forcing all developers onto it.
However, given that I’ve had to change all my extensions over, it’s a real pain that I have to maintain two separate versions of each: one in mv3 for chrome and edge and another in mv2 for Firefox.