To uninstall debian-edu-doc-de just follow these instructions.
/debian/stretch/main///install/index.html German documentation from the Debian Edu project Debian 9.0 doc 1.921~20170603
sudo apt-get remove debian-edu-doc-de
Which will remove just the debian-edu-doc-de package itself.
sudo apt-get remove --auto-remove debian-edu-doc-de
This will remove the debian-edu-doc-de package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for debian-edu-doc-de then this will work.
sudo apt-get purge debian-edu-doc-de
Or similarly, like this debian-edu-doc-de
sudo apt-get purge --auto-remove debian-edu-doc-de
|Maintainer||Debian Edu Developers
|Description||German documentation from the Debian Edu project|