XmClipboardStartCopy(3) on Linux
The text f0f62712c9c4, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A clipboard function that sets up a storage and data structure "XmClipboardStartCopy" "clipboard functions" "XmClipboardStartCopy"