MrmRegisterClass(3) on Linux
The text 5890ca2f4fc3, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
Saves the information needed for MRM to access the widget creation function for user-defined widgets "MrmRegisterClass" "uil functions" "MrmRegisterClass"