XmMainWindowSetAreas(3) on Linux
The text c8bc233a9c10, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A MainWindow function that identifies manageable children for each area "XmMainWindowSetAreas" "MainWindow functions" "XmMainWindowSetAreas"