FreeDict-Editor is unmaintained!
The documentation coming with this application includes the list of features in the introduction.
No release of the FreeDict-Editor has been made yet. You can checkout the freedict-editor directory from git and try compiling it yourself:
git clone --depth=1 --no-checkout https://github.com/freedict/fd-dictionaries.git && \ cd fd-dictionaries && \ git --work-tree=`pwd` checkout HEAD -- freedict-editor
For the requirements, please also refer to the documentation.
If you use Debian unstable, you can add this to your /etc/apt/sources.list:
deb http://freedict.org/debian-repository unstable main
deb-src http://freedict.org/debian-repository unstable main