Even with "strict" tracking prevention Linux is still in the user agent string. That's been very reliably IME.

"Linux x86_64" is present on my UA on Linux, and "Windows NT 10.0; Win64; x64" on Windows. Probably a bug or just untested on Firefox. Just a bit annoying.

I'll add that this is the first site that misdetects anything like that.

Is it because of tracking protection/fingerprinting protection being on by default?