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Your Chrome extensions may stop working in 2024
(www.ghacks.net)
This is a most excellent place for technology news and articles.
There isn't much, Waterfox removes Pocket and disables most of the telemetry, tweaks some of the settings to be more privacy and performance minded, swaps google from default search engine and iirc it has more aggressive compiler optimization settings in exchange for having slightly more modern hardware requirements. And the default theme is more compact and less chrome-esque.
It originally was just about providing 64-bit builds of Firefox back when Mozilla didn't yet, today it's mostly "Firefox, but slightly better."