I really had to go and disable that. I use a lot of tabs, I switch between them often, and a few of them stay open for a while

I have tree style tabs so my tabs are all already ordered in a vaguely meaningful way, but the recent use order of my last tabs is completely unpredictable to me!

With this feature on ^tab might as well be random for how badly it confuses me.. I'm so glad Mozilla hadn't removed the opt-out yet.