Assuming both the ad and the JS to track said ad are served from a 3rd party (or at least a different domain)

Yes, that’s what I’m saying. I believe that’s mostly the case, especially because websites serve ads from ad networks owned by others. Even in the same company, they’ll often be served from specific domains due to technical decisions.

although without recordings of impressions the utility of that (and privacy risk) is debatable.

If there’s no impression, there’s never any conversion. As long as uBlock is doing its job, you pretty much don’t have to worry about PPA… though, feel free to simply turn if off anyway. That’s why they added a toggle, after all.

Ads are a plague, you give them even an inch and they’ll eventually take everything.

Oh, on that we agree. Billboards don’t track physical eyeballs that land on them, so why would virtual ads deserve all these privileges? I think they only manage because they normalized the practice before anyone could stop them, and now we’re all stuck in this hell.

Firefox was one of the last bastions that seemed to be working with us instead of against us.

I trust it still is. Or, at bare minimum, it remains much better than most alternatives.

It’s the first step along a path we don’t want to go down.

I try to always be fair in discussions, even if it means sharing crappy stuff. So I’m very sorry to tell you, but it really isn’t. Back when DRM was implemented, for example, that was an entire mess, with Firefox eventually moving forwards with the implementation in a great compromise. As in, one that left everyone unsatisfied, but allowed users to watch Netflix.

Here’s something interesting to keep in mind when trying to understand Mozilla’s actions, from the Manifesto:

Principle 9

Commercial involvement in the development of the internet brings many benefits; a balance between commercial profit and public benefit is critical.