https://bugzilla.redhat.com/show_bug.cgi?id=1531986
--- Comment #2 from Mingye Wang arthur200126@gmail.com ---
I think maybe good to not change default Chinese fonts by installing fonts packages.
UMing is attempting to do so with the "prepend" directives its fontconfig file. It fails because Fedora has other defaults. Parts of its attempts -- those adding it to sans-serif -- are nevertheless wrong. And "Sans" is short for sans-serif FYI.
UMing/UKai fonts are for Traditional Chinese, not for Simplified Chinese.
There are CN variants. You might be thinking it is for Trad. because it is not complying well with Chinese standards, but guess what it's not very TW/HK-compliant either. And people still use it in TW and HK!
If you are thinking it's not for Simp. because it's called a "Ming", then nobody should be using Source Han Serif for Trad and Japanese because it's called a "Song".
Compared to Source Han Sans CN, both UMing and UKai are Serif fonts, I think.
Fontconfig uses generic families beyond sans-serif, serif, and monospace. You can read those files numbered 60 to 69 in conf.avail for a sense of it. There's "cursive" for handwritten stuff[^1] like Kai and Comic Sans. There's also "fantasy" for crazy-looking things like "impact".
[^1]: my bad, I've been calling it "script". I will re-test 1531985.