Bad news is that it is not clear at this point whether Mozilla is going to go forward with the implementation. A post on Reddit by one of the project members suggests that the build is a “rough proof-of-concept”. Some features tested in the build “did not survive”. It is unclear which did not, as they are not mentioned. Mozilla is, however, implementing those that survived the cut into Firefox. Again, the poster does not mention which those are. It is also not verified that the poster is actually a member of the project team, so take this with a grain of salt as well.

Those screenshots look really nice, ngl, hoping this goes through. Edge and Vivaldi have had their own vertical tab implementations for a while now, and there are Firefox forks that show it can be done. No reason for base Firefox not to have it at this point.

While I’m here, Mozilla bring back compact spacing, plz k thx.

Edit: Just tried it, it’s got that nightly jank but it’s promising. I hope Mozilla continues with this. It looks and feels great.

I would love the option of keeping containers in vertical tabs with “page tabs” horizontal. For example; Facebook, Personal, Banking, Work, Incognito, etc containers along the left as vertical tabs, and each one has all the pages in tabs across the top. Vertical tabs only appear after you open more than one type of container.