A web page that tells you what your browser gave away the moment you arrived. No login, no form, no permission. Most pages do this. None of them tell you.
The site could also be set to display whatever font it wants but also set to list standard fonts that also work which the browser can then choose from on the user’s end if the user doesn’t have the first choice font. That way you the user don’t have to worry about it and there is no way to fingerprint by the browser just handing out an entire list of fonts installed on the user’s system. There are plenty of ways to make things like this work, but the incentive is to keep them as they are or to increase uniqueness so people can be more easily fingerprinted.
The site could also be set to display whatever font it wants but also set to list standard fonts that also work which the browser can then choose from on the user’s end if the user doesn’t have the first choice font. That way you the user don’t have to worry about it and there is no way to fingerprint by the browser just handing out an entire list of fonts installed on the user’s system. There are plenty of ways to make things like this work, but the incentive is to keep them as they are or to increase uniqueness so people can be more easily fingerprinted.