Yup, it's true. Firefox 128 includes new adtech features that are turned on by default and announced with very little fanfare, so most people might not even know they're there.  

Well, this is me telling you they're there. You might want to go ahead and take a minute to opt out.

Here's the little helpful explainer from Mozilla about how it all works:

https://support.mozilla.org/en-US/kb/privacy-preserving-attribution

My read seems to be: Mozilla says website surveillance is generally bad and should be defended against. Cool. No notes. Firefox actually has a lot of nice anti-tracking and privacy features there and that's the main reason why I like Firefox.

But, and I swear I'm not even joking a little bit here, Mozilla goes on to say that advertisers might be happier if Firefox itself just tracked you directly and sent activity reports back to them.

Doesn't that sound great?

Now, to Mozilla's credit, they claim to anonymize the activity reports. And you can still meaningfully opt out of the whole system.

But WTF, mate?! I use Firefox *because* it fights against adtech. Or at least it used to. Now, Mozilla just lets adtech right in the front door and hopes you won't notice?  

Well, we noticed. Mozilla is damage and we need to route around it.

UPDATE: The about:config setting for this is `dom.private-attribution.submission.enabled`. It's a bool. Set it to false to turn it off.

Privacy-Preserving Attribution | Firefox Help

Firefox 128 introduces privacy-preserving attribution, allowing advertisers to measure campaign performance while protecting user privacy.

@cuchaz obligatory librewolf mention. Removes all of the "what the fuck are you doing Mozilla" anti-features and keeps the useful ones that actually enhance privacy. https://librewolf.net/
LibreWolf Browser

A custom version of Firefox, focused on privacy, security and freedom.

@prettygood @cuchaz

Yeah, and if they ever allow Dark Mode with Data Protect(?) enabled, I'll use it.

Anti-fingerprinting? FFS.

@avoca @cuchaz you can always install a different theme that is something other than the default dark theme. Or, you know, turn off the fingerprinting setting, if dark mode is that much more important to you.

@prettygood @cuchaz

Nah, I just moved over to Brave.

The way Mozilla are seemingly headed it was only a matter of time anyway.

Cheers though.

@cuchaz @avoca @prettygood I use the dark reader plugin, though I’m not sure if this is the way to do it that breaks fingerprinting the least. Idk what’s worse, having it send requests to use dark mode to websites, or making websites have a dark mode appearance on the client side but having one more (commonly used, but still) plugin? Idk
@prettygood @cuchaz @avoca the FAQ of librewolf suggests people set that up manually for every website they use that has a dark mode setting, which is just a hassle and involves trying to find that setting and then setting up cookie exceptions, and it doesn’t work if a website doesn’t have that setting or if you just want to idk search things, use websites other than the few you commonly use. It’s just not a viable solution, at least not for me.
@cuchaz @avoca @prettygood and keep in mind that dark mode is an accessibility thing for some people, this isn’t always just some insignificant personal preference or sth. And even if it wasn’t, people should have the option and there should be information about how to set this up in a way that impacts fingerprinting the least other than manually setting it for every website, so that they can make an informed decision. People can’t just expect everyone’s priorities to be the same.