Why desktop files should go to /usr/share/applications ?

[Loic Pefferkorn]

Hello,

Where can I find an official specification for path of desktop files for KDE 
apps ? 
Some apps uses /usr/share/applnk, but /usr/share/applications seems to be 
recommended.

I've found something about XDG dirs :

http://lists.debian.org/debian-kde/2004/02/msg00132.html

But I wish something more "official" like Debian policy.

Regards,
Loic