[chjj]

I tried doing that in the early 2010s. Even back then it didn't work (github broke for example). If you did it today, you'd likely be blocked by a lot of major websites for "lying" about your user agent. Cloudflare turnstiles will stop working, you'll get captcha'd to death, and so on.

Even tor-browser doesn't dare to modify the user agent string in any major way. It's almost impossible to lie about because trackers don't actually care about your user agent. They're identifying your device/OS through side channels (canvas, webgl, fonts, etc).

[npteljes]

Wrt/ Tor browser, it's not that they don't dare to, it's that they don't want to. One of the goals of that browser is to not stick out too much, and changing the user agent would do just that, so they don't do it.

[chjj]

Then the ideal would be to normalize the user agent string to look identical on every platform. My point is: they can't do that. e.g. A linux machine identifying itself as windows would be spotted immediately. Instead, they have to reduce entropy by bucketing you according to your device/OS/arch.