XmGetColors(3) on Linux
The text 39cca72ae4e8, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A function that generates foreground, select, and shadow colors "XmGetColors" "Color functions" "XmGetColors"