Why did they remove the OS spoofing? Without having read the controversy, my guess is that "TOR Browser doesn't work" needed a fix and a big part of the problem was that users on Linux got the Windows version of websites, so the TOR browser devs decided to tell the website this detail about the visitor, resulting in reducing the anonymity set dramatically, to 2.5% but even worse, to the 2.5% that are most suspicious to totalitarian regimes cause it must be somebody with agency and initiative, who doesn't just go with the OS that came with the PC.