To uninstall debian-edu-artwork-lines just follow these instructions.
/debian/stretch/main///install/index.html Debian Edu Lines (jessie) themes and artwork Debian 9.0 graphics 0.902-3
sudo apt-get remove debian-edu-artwork-lines
Which will remove just the debian-edu-artwork-lines package itself.
sudo apt-get remove --auto-remove debian-edu-artwork-lines
This will remove the debian-edu-artwork-lines package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for debian-edu-artwork-lines then this will work.
sudo apt-get purge debian-edu-artwork-lines
Or similarly, like this debian-edu-artwork-lines
sudo apt-get purge --auto-remove debian-edu-artwork-lines
|Maintainer||Debian Edu Developers
|Description||Debian Edu Lines (jessie) themes and artwork|