Reconsider .desktop menu categories
MAT is currently listed in the category "System Tools" in the menu of GNOME in Tails. This should be changed thus MAT is not a System Tool. (removing the entry "System" from the .desktop file moves it into "Accessories" in the menu, this could be one solution, but other opinions are welcome!)
(from redmine: created on 2016-03-18, relates #11248)