XmVaCreateManagedOutline(3) on Linux
The text 4448072a411e, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A Outline widget convenience creation functions. "XmVaCreateOutline" "XmVaCreateManagedOutline" "creation functions"