>Sadly it builds on an unstable API and is quite a bit of work to get it installed in FF.
I didn't seem to have any issues getting the add-on installed in my Firefox. Yes, TST suffered from some instability when Firefox initially deprecated XUL and switched to the WebExtension model exclusively, but it seems to work fine now. It even picked up the theming changes in the latest update to Firefox seamlessly.
>I think this kind of approach to tabs deserves to land upstream in browsers
Edge comes close. It has the option to orient tabs vertically. However, it doesn't organize tabs in a hierarchical outline like TST does.
There’s also Orion, at least on Mac. It hasn’t replaced my daily driver (Brave), but I’ve been using it as a ‘container’ of sorts for LinkedIn and have found it to be pretty good.
Brave currently has vertical tabs as a flag-enable-able option, and if they add tree hierarchy, I probably won’t switch. But if not, I’ll likely move to Orion, which has been working well for me.
I didn't seem to have any issues getting the add-on installed in my Firefox. Yes, TST suffered from some instability when Firefox initially deprecated XUL and switched to the WebExtension model exclusively, but it seems to work fine now. It even picked up the theming changes in the latest update to Firefox seamlessly.
>I think this kind of approach to tabs deserves to land upstream in browsers
Edge comes close. It has the option to orient tabs vertically. However, it doesn't organize tabs in a hierarchical outline like TST does.