XSetClassHint(3) on Linux
The text 9ab96eac4c94, as Debian 12 (Bookworm) shipped it.
allocate class hints structure and set or read a window's WM_CLASS property
The text 9ab96eac4c94, as Debian 12 (Bookworm) shipped it.
allocate class hints structure and set or read a window's WM_CLASS property