XmFontListRemoveEntry(3) on Linux
The text b9a0de6c08aa, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A font list function that removes a font list entry from a font list "XmFontListRemoveEntry" "font list functions" "XmFontListRemoveEntry"