[pdonis]

> Does that make it more clear what's going on?

No. I already understand why non-default zoom gives websites a way to fingerprint you, if your browser insists on telling the websites that you have a non-default zoom level.

What I don't understand, and what nobody in this discussion has been able to explain, is why a browser with privacy.resistFingerprinting = true can't just lie to the website about what the zoom level is. You have said that zoom should be a local operation; that means the browser shouldn't have to tell the website anything about the actual zoom level if the user doesn't want it to. It should just load the page, telling the website whatever default things it tells the website when privacy.resistFingerprinting = true, including, presumably, a default zoom level, and then do the local zoom operation afterwards.