486
You asked, we built it: Firefox tab groups are here | The Mozilla Blog
(blog.mozilla.org)
A place to discuss the news and latest developments on the open-source browser Firefox
Doesn't seem to indicate whether groups will work with vertical tabs and unless that's the case, I'm not switching from TST.
I've been using tab groups with vertical tabs. No issues here. I'm on stable.
They do work in vertical tabs, but only one level. You can't have nested tabs as far as I can tell.