212
Vivaldi's tab tilling add-on in Firefox
(lemmy.dbzer0.com)
A place to discuss the news and latest developments on the open-source browser Firefox
Floorp, a browser based on Firefox, has Workspaces I believe (along a LOT of other stuff). Might be worth checking out.
Their website is in Japanese, but the GitHub page is in English. I’m sleepy and too lazy to link stuff right now, sorry.
If they have stacking tabs, I'm in