curs_bkgd(3x) on macOS
The text 9f5be87d4280, as macOS 13.5, macOS 13.4, macOS 13.3, macOS 13.2, macOS 13.1, macOS 13.0, macOS 12.5, macOS 12.4, macOS 12.3, macOS 12.2, macOS 12.1, macOS 12.0.1 shipped it.
curses window background manipulation routines