zlacker

An integrated experience. In the past I found that the vertical tab options in Firefox had the tabs duplicated across the side and the top, which I always found to be a subpar experience. Again, probably something you could accomplish with user.js and user.css but there's a good chance an update could break your modifications.

>>chryso+(OP)
If you haven't tried firefox' vertical tabs recently, try it again. Firefox's default vertical tabs UI is quite nice now.

>>gcr+t
Seems quite similar to Zen's experience, except it seems to be missing folders (which I admittedly don't use often, but they're sometimes handy to group a Jira ticket with a PR, or similar). I'll probably still stick with Zen while it's around, and maybe I'll hop over to LibreWolf as I'm not too happy about Mozilla's recent stance on privacy.

>>chryso+i1
Is it similar to tab groups? It's available on Firefox Nightly, don't know about stable.

>>Futuri+S1
Maybe! Folders in Zen let you group, label and collapse tabs, so if that's the same thing then yes.

>>gcr+t
I found it too buggy in my usage, it just doesn't compare to the polish in Zen or the other forks. Better just to use the horizontal tabs IMO.