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Firefox 129.0 Release Notes
(www.mozilla.org)
A place to discuss the news and latest developments on the open-source browser Firefox
I use tree style tabs and it also has an option to unload tabs. I might be wrong and there is a plugin for TST that adds this functionality though.
SideBery lets you unload whole groups of them!
(This tab grouping is not quite as good as what Chrome and derivatives have, but it's very close.)