[floriancargoet]

It's not a real package name, it's a tasksel task.

Quick explanation: http://askubuntu.com/q/211912

Differences between apt-get and taskel: http://askubuntu.com/a/257172

[koenigdavidmj]

This used to be done by metapackages (a .deb containing no files but having dependencies on everything in...GNOME, for instance). Why this new thing?