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Why is Firefox making these outbound connections?
(infosec.pub)
A place to discuss the news and latest developments on the open-source browser Firefox
Sounds like it's pretty standard, benign stuff. Luckily FF is open source, so if this freaks you out, then try one of the more private forks like LibreWolf. You won't see these same connections there.
Fresh install of LibreWolf and it's made a bunch of outbounds. Some seems related to it auto-installing uBlock. Others similar to default FF.