the author of TST is refusing donations AFAIK. He also said a lot of blockages came from Firefox and not from himself. I find it a bit sad that Firefox is not making TST a prime feature of Firefox. Are no Firefox developers using TST? I find that surprising.
It's possible most of them are now using the combination of tab containers and the "snooze tabs" extension, rather than trees. A test pilot feature that lets you mark tabs as "I don't want to see you until tonight/tomorrow morning/the weekend/next week/etc". It really cuts down on the need to keep 100+ tabs open (you just silo the tabs based on their role, then snooze all the ones you don't want to lose but don't need in the slightest right now either).
I've tried the snooze things for other things and I just ended up snoozing things again and again. Nowadays it's typical to have 10-20+ tabs open at all time that you're going to need during the day. That's already too much for tabs on top
