In fact, it would seem to me that the ideal useragent is this: Mozilla/5.0 (Unknown; Linux; rv:57.0) Gecko/20100101 IceWeasel/57.0 - it doesn't depend on the setup.

Just noticed #1560, but I think that it's more important for users to have a free user agent by default, as the Windows useragent is something that people aren't likely to notice, whereas people who want the Windows useragent will probably know how to change to it, or at least be aware that the default useragent isn't something they want.

Let's get our definitions straight: there is no such thing as a nonfree user agent. A small string mentioning proprietary software and the software itself aren't the same thing.

The practice was probably copied from GNU Icecat, where the Windows user agent is employed to protect users from tracking by default. Would you rather have users unsuspectingly report they are using your average nonfree platform or make them easy prey to miners?