> No mention of whether the feature is available now on a stable release
> Looking at some of the 20 year old bugs that still exist?
https://gbhackers.com/google-to-patch-23-year-old-chrome-bug/
From the support page: https://support.mozilla.org/en-US/kb/tab-groups
> This feature is experimental and is being introduced to the Firefox user base through a progressive rollout. It may not yet be available to all users.
I'll wait a few more days then I guess?