/usr/share/desktop-directories/ is in education-menus 1.812+deb8u1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/desktop-directories/Astronomy.directory
/usr/share/desktop-directories/Chemistry.directory
/usr/share/desktop-directories/DebianEdu.directory
/usr/share/desktop-directories/Economy.directory
/usr/share/desktop-directories/Electricity.directory
/usr/share/desktop-directories/Geography.directory
/usr/share/desktop-directories/Kids.directory
/usr/share/desktop-directories/Languages.directory
/usr/share/desktop-directories/Literature.directory
/usr/share/desktop-directories/Mathematics.directory
/usr/share/desktop-directories/Miscellaneous.directory
/usr/share/desktop-directories/Music.directory
/usr/share/desktop-directories/Physics.directory
/usr/share/desktop-directories/Sports.directory