XmTextFieldReplaceWcs(3) on Linux
The text e51d9029ae7a, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
A TextField function that replaces part of a wide character string in a TextField widget "XmTextFieldReplaceWcs" "TextField functions" "XmTextFieldReplaceWcs"