/usr/share/desktop-base/grub_background.sh is in sabily-grub-artwork 1.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | WALLPAPER=/usr/share/images/grub/sabily.png
COLOR_NORMAL=black/black
COLOR_HIGHLIGHT=magenta/black
|