Firefox

Yeah repositories and FTP don't include that, but it is kind shady that the first way to get it (website) for the majority of regular users (Windows/macOS) has a unique ID - after all this is the company that goes all in for privacy...

Must be for ad attribution and install tracking. Only something a major portion of their users are specifically trying to avoid when they're choosing Firefox.

Nothing, not everyone liked it, the only difference is that my comment would result in a shit show of downvotes last week while not people are starting to realize what Mozilla/Firefox really is. Mozilla was never the "all savior" pained them to be and it only took Wireshark and a couple of minutes to see it.

I have this in user.js:

// settings user-test-programm
user_pref("app.shield.optoutstudies.enabled", false);

// dont use me as guinea pig
user_pref("app.normandy.enabled", false);
user_pref("app.normandy.optoutstudies.enabled", false);
user_pref("messaging-system.rsexperimentloader.enabled", false);

// side-loading of telemetry-extension
user_pref("extensions.systemAddon.update.enabled", false);

// disable Mozillas new tracking aggragation thingy
user_pref("dom.private-attribution.submission.enabled", false,);

// almost only for tracking useful
user_pref("beacon.enabled", false); // so webpage can send (tracking) data before you close tab
user_pref("browser.send_pings", false); // hyperlink auditing (click-tracking)

Note: the last two are more nuanced.

Argument for beacon is that webpages will use a more intrusive way with noticeable delay to upload data on tab close. I personally prefer that, as a warning, but never saw one after years.

Argument for send_pings is, that trackers will use more mean and stealthier ways to track you, if they don't have that interface (same as in private-attribution). I do know however, that companies who track you have high greed and low morale to begin with, and use all they can get to generate more money.

That is blatantly false. Don't even waste your time.

Just fire up Wireshark and inspect what Firefox calls, a lot of calling home and even if you change all the settings and config parameters to something sane it will still contact a 3rd party analytics company. Mozilla also acquired an ad analytics company recently for some reason.