Well, fedoraproject.org is not for mobile and it's a redirect, but anyway, results on this kind of tests are relative. The website is working fine on mobile, I don't think there is much to optimize for now. Many other websites, also well known websites, get even worse results in this test, maybe they get better ones in other tests. It depends which you are looking at...

Mobile just happens to be the first tab. the second one is desktop

https://developers.google.com/speed/pagespeed/insights/?url=fedoraproject.org&tab=desktop

Most of the optimizations are common across the profiles. Other sites may do worse or better but that isn't particularly relevant here.