Extension rundown:
— kesselborn’s Conex, a Spotlight-like quick container switcher/tab finder. It’s set to auto-hide tabs not in the current container, and I use it to routinely create one-off containers for specific tasks
— piro’s Tree Style Tab, with a workaround setting to make it play well with Conex and a couple of custom styling rules
— MarsCat’s Switch Container, which allows to re-open a tab in another container (used with caution)
What unblocked the switch for me:
— There’s now a working tree-style tabs extension in Quantum
— The new Web Authentication API removes the need for Keychain integration in the long run
I’m wary of getting too used to a heavily customized setup, and am still figuring out the best way to back up my Firefox profile. Previously I relied mostly on stock Safari and Chrome, which is still great for its developer’s tools.