$ ls -ld /usr/src/*source*
-rw-r--r-- 1 root root 41376773 Mar 26 2007 /usr/src/linux-source-2.6.18.tar.bz2
-rw-r--r-- 1 root root 45611846 Dec 21 13:16 /usr/src/linux-source-2.6.23.tar.bz2
lrwxrwxrwx 1 root src 21 Jan 14 13:13 /usr/src/nvidia-kernel-source.tar.bz2 -> nvidia-kernel.tar.bz2
$ apt-cache policy
Package files:
100 /var/lib/dpkg/status
release a=now
800 http://edevelop.org unstable/non-free Packages
release o=edevelop.org,a=unstable,l=e17,c=non-free
origin edevelop.org
800 http://edevelop.org unstable/contrib Packages
release o=edevelop.org,a=unstable,l=e17,c=contrib
origin edevelop.org
800 http://edevelop.org unstable/main Packages
release o=edevelop.org,a=unstable,l=e17,c=main
origin edevelop.org
800 http://www.debian-multimedia.org unstable/main Packages
release o=Unofficial Multimedia Packages,a=unstable,l=Unofficial Multimedia Packages,c=main
origin www.debian-multimedia.org
800 http://ftp.fr.debian.org unstable/contrib Packages
release o=Debian,a=unstable,l=Debian,c=contrib
origin ftp.fr.debian.org
800 http://ftp.fr.debian.org unstable/non-free Packages
release o=Debian,a=unstable,l=Debian,c=non-free
origin ftp.fr.debian.org
800 http://ftp.fr.debian.org unstable/main Packages
release o=Debian,a=unstable,l=Debian,c=main
origin ftp.fr.debian.org
900 http://deb.opera.com testing/non-free Packages
release o=Opera Software ASA,a=testing,l=The Opera web browser,c=non-free
origin deb.opera.com
900 http://www.debian-multimedia.org testing/main Packages
release o=Unofficial Multimedia Packages,a=testing,l=Unofficial Multimedia Packages,c=main
origin www.debian-multimedia.org
900 http://ftp.debian-unofficial.org testing/restricted Packages
release o=Debian Unofficial,a=testing,l=Debian Unofficial,c=restricted
origin ftp.debian-unofficial.org
900 http://ftp.debian-unofficial.org testing/non-free Packages
release o=Debian Unofficial,a=testing,l=Debian Unofficial,c=non-free
origin ftp.debian-unofficial.org
900 http://ftp.debian-unofficial.org testing/contrib Packages
release o=Debian Unofficial,a=testing,l=Debian Unofficial,c=contrib
origin ftp.debian-unofficial.org
900 http://ftp.debian-unofficial.org testing/main Packages
release o=Debian Unofficial,a=testing,l=Debian Unofficial,c=main
origin ftp.debian-unofficial.org
950 http://security.debian.org testing/updates/contrib Packages
release o=Debian,a=testing,l=Debian-Security,c=contrib
origin security.debian.org
950 http://security.debian.org testing/updates/non-free Packages
release o=Debian,a=testing,l=Debian-Security,c=non-free
origin security.debian.org
950 http://security.debian.org testing/updates/main Packages
release o=Debian,a=testing,l=Debian-Security,c=main
origin security.debian.org
900 http://ftp.fr.debian.org testing/contrib Packages
release o=Debian,a=testing,l=Debian,c=contrib
origin ftp.fr.debian.org
900 http://ftp.fr.debian.org testing/non-free Packages
release o=Debian,a=testing,l=Debian,c=non-free
origin ftp.fr.debian.org
900 http://ftp.fr.debian.org testing/main Packages
release o=Debian,a=testing,l=Debian,c=main
origin ftp.fr.debian.org
990 file: apt-build/main Packages
release o=apt-build,l=apt-build,c=main
Pinned packages:
Il y a une chose curieuse avec ce policy: Toute la journée et depuis plusieurs jours j’avais des entrées en 500 pour les Translation-fr … et elles n’y sont plus ! 
$ apt-cache policy nvidia-kernel-source
nvidia-kernel-source:
Installed: 169.07-2
Candidate: 169.07-2
Version table:
*** 169.07-2 0
800 http://ftp.fr.debian.org unstable/non-free Packages
100 /var/lib/dpkg/status
$ less /etc/atp/sources.list
deb file:/var/cache/apt-build/repository/ apt-build main
deb http://ftp.fr.debian.org/debian/ testing main non-free contrib
deb-src http://ftp.fr.debian.org/debian/ testing main non-free contrib
deb http://security.debian.org/ testing/updates main non-free contrib
deb-src http://security.debian.org/ testing/updates main non-free contrib
deb http://ftp.debian-unofficial.org/debian/ testing main contrib non-free restricted
deb http://www.debian-multimedia.org/ testing main
deb http://deb.opera.com/opera testing non-free
deb http://ftp.fr.debian.org/debian/ unstable main non-free contrib
deb http://www.debian-multimedia.org/ unstable main
deb http://edevelop.org/debian/ unstable main contrib non-free