>On the other hand, I am surprised they correctly identify my "platform" as "Linux x86_64". Even though I used a windows user agent. How do they do that?
probably because your user agent faker only fakes the http header and not the javascript environment.
try printing out the value of navigator.userAgent or navigator.platform in the developer console.
There is even more stuff in navigator, that should not be accessible to the website. For example how much ram my machine has in navigator.deviceMemory, how many cpu cores in navigator.hardwareConcurrency and so on.
privacy.resistFingerprinting has a bunch of useful features (this, letterboxing, etc) that I wish were available under their own dedicated about:config options. I don't want to enable resistFingerprinting because I value being able to use dark mode more.
probably because your user agent faker only fakes the http header and not the javascript environment.
try printing out the value of navigator.userAgent or navigator.platform in the developer console.