/usr/sbin/update-debian-edu-artwork-joy is in debian-edu-artwork-joy 0.52-2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | #! /bin/sh
set -e
EDUTHEME="joy"
change_ldm_background() {
	update-alternatives --install /usr/share/ldm/themes/default \
	    ldm-theme /usr/share/ldm/themes/debian-edu-${EDUTHEME} 85
	update-alternatives --set ldm-theme \
	    /usr/share/ldm/themes/debian-edu-${EDUTHEME}
}
restore_ldm_background() {
	update-alternatives --remove ldm-theme /usr/share/ldm/themes/debian-edu-${EDUTHEME}
}
## GRUB
change_grub_background() {
	priority=50 # value higher than 20 used for ${EDUTHEME}-grub.png in desktop-base
	update-alternatives --install \
	    /usr/share/images/desktop-base/desktop-grub.png \
	    desktop-grub \
	    /usr/share/pixmaps/splash/debian-edu-${EDUTHEME}-splash-grub.png $priority
	update-alternatives --set desktop-grub \
	    /usr/share/pixmaps/splash/debian-edu-${EDUTHEME}-splash-grub.png
	ln -sf debian-edu-${EDUTHEME}-splash.png /usr/share/pixmaps/splash/debian-edu-splash.png
	if which update-grub2 > /dev/null ; then
		sync
		update-grub2 || true
	fi
}
restore_grub_background() {
	update-alternatives --remove desktop-grub \
	    /usr/share/pixmaps/splash/debian-edu-${EDUTHEME}-splash-grub.png
	rm -f /usr/share/pixmaps/splash/debian-edu-splash.png
	if which update-grub2 > /dev/null ; then
		update-grub2 || true
	fi
}
## Wallpaper
change_desktop_background() {
	update-alternatives --install \
	    /usr/share/images/desktop-base/desktop-background \
	    desktop-background \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}-wallpaper01_1920x1080.svg 75
	update-alternatives --set desktop-background \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}-wallpaper01_1920x1080.svg
	update-alternatives --install \
	    /usr/share/images/desktop-base/desktop-background.xml \
	    desktop-background.xml \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}.xml 20
	update-alternatives --set desktop-background.xml \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}.xml
	for WALLPAPER in debian-edu-${EDUTHEME}-wallpaper01_1280x1024.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1600x1200.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1920x1080.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1920x1200.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1280x1024.svg; do
		update-alternatives --install \
		    /usr/share/images/desktop-base/desktop-background \
		    desktop-background \
		    /usr/share/images/desktop-base/$WALLPAPER 50
	done
}
restore_desktop_background() {
	update-alternatives --remove \
	    desktop-background \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}-wallpaper01_1920x1080.svg
	update-alternatives --remove \
	    desktop-background.xml \
	    /usr/share/images/desktop-base/debian-edu-${EDUTHEME}.xml
	for WALLPAPER in debian-edu-${EDUTHEME}-wallpaper01_1280x1024.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1600x1200.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1920x1080.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1920x1200.svg \
	                 debian-edu-${EDUTHEME}-wallpaper01_1280x1024.svg; do
		update-alternatives --remove desktop-background \
		    /usr/share/images/desktop-base/$WALLPAPER
	done
}
## Wallpaper
change_ksplash() {
	update-alternatives --install \
	    /usr/share/images/desktop-base/desktop-splash \
	    desktop-splash \
	    /usr/share/kde4/apps/kdm/themes/debian-edu-${EDUTHEME}/background.svg 55
	update-alternatives --set desktop-splash \
	    /usr/share/kde4/apps/kdm/themes/debian-edu-${EDUTHEME}/background.svg
}
restore_ksplash() {
	update-alternatives --remove desktop-splash \
	    /usr/share/kde4/apps/kdm/themes/debian-edu-${EDUTHEME}/background.svg
}
compile_gschemas() {
	if [ -d /usr/share/glib-2.0/schemas/ ] && [ -x /usr/bin/glib-compile-schemas ]; then
		glib-compile-schemas /usr/share/glib-2.0/schemas/
	fi
}
symlink_login_background() {
	if [ -f /usr/share/images/desktop-base/login-background.svg.edu-diverted ]; then
		ln -fs /usr/share/images/desktop-base/debian-edu-${EDUTHEME}-wallpaper02_1600x1200.svg /usr/share/images/desktop-base/login-background.svg
	fi
}
symlink_gnome_shell_css() {
    if [ -f /usr/share/gnome-shell/theme/gnome-shell.css.edu-diverted ]; then
	ln -fs /usr/share/gnome-shell/theme/debian-edu-${EDUTHEME}-gnome-shell.css /usr/share/gnome-shell/theme/gnome-shell.css
    fi
}
unlink_gnome_shell_css() {
    if [ -h /usr/share/gnome-shell/theme/gnome-shell.css ] && \
       [ "$(readlink /usr/share/gnome-shell/theme/gnome-shell.css)" = "/usr/share/gnome-shell/theme/debian-edu-${EDUTHEME}-gnome-shell.css" ]; then
	rm -f /usr/share/gnome-shell/theme/gnome-shell.css
    fi
}
symlink_kde_base_edu_js() {
	if [ -f /usr/share/debian-edu-artwork-${EDUTHEME}/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js ]; then
		ln -fs /usr/share/debian-edu-artwork-${EDUTHEME}/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js /usr/share/kde4/apps/plasma-desktop/init/
	fi
}
unlink_kde_base_edu_js() {
	if [ -h /usr/share/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js ] && \
	   [ "$(readlink /usr/share/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js)" = "/usr/share/debian-edu-artwork-${EDUTHEME}/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js" ]; then
		rm -f /usr/share/kde4/apps/plasma-desktop/init/20-desktop-base-edu.js
	fi
}
case "$1" in
	configure)
		change_ldm_background
		change_grub_background
		change_desktop_background
		change_ksplash
		compile_gschemas
		symlink_login_background
		symlink_kde_base_edu_js
		symlink_gnome_shell_css
	;;
	remove)
		restore_ldm_background
		restore_grub_background
		restore_desktop_background
		restore_ksplash
		compile_gschemas
		unlink_kde_base_edu_js
		unlink_gnome_shell_css
	;;
esac
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