XmRepTypeGetId(3) on Linux
The text 72eff30b6813, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A representation type manager function that retrieves the identification number of a representation type "XmRepTypeGetId" "representation type manager functions" "XmRepTypeGetId"