fontconfig ignores generic family system-ui rules
In Arch Linux for a new user without any user customizations
$ fc-match system-ui
NimbusSans-Regular.otf: "Nimbus Sans" "Regular"
This is strange since /etc/fonts/conf.d/45-latin.conf
and /etc/fonts/conf.d/60-latin.conf
set it to Cantarell
which is already available. There is no rule whatsoever by default to set "Nimbus Sans"
as a system-ui
font.
It seems fontconfig
just ignores system-ui
as can be verified by
diff <(fc-match -s sans-serif) <(fc-match -s system-ui)
So, it just fallback to sans and inherited its rules.
Attached is the output of FC_DEBUG=4 fc-match system-ui
FC_DEBUG4-fc-match-system-ui