~$ apt-cache policy thunderbird
thunderbird:
  Installiert: 12.0.1+build1-0ubuntu0.10.04.1
  Kandidat: 12.0.1+build1-0ubuntu0.10.04.1
  Versions-Tabelle:
 *** 12.0.1+build1-0ubuntu0.10.04.1 0
        500 http://security.ubuntu.com/ubuntu/ lucid-security/main Packages
        500 http://archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
        100 /var/lib/dpkg/status
     3.0.4+nobinonly-0ubuntu4 0
        500 http://archive.ubuntu.com/ubuntu/ lucid/main Packages