http://debian.fam.cx/index.php?AptGet#x5a412bf
backports とか拾ったパッケージとかを抽出するには apt-show-versions を使う。
$ apt-show-versions |grep -v "/squeeze " brscan-skey 0.2.1-3 installed: No available version in archive brscan4 0.3.0-3 installed: No available version in archive dcpj925ncupswrapper 1.1.2-1 installed: No available version in archive dcpj925nlpr 1.1.2-1 installed: No available version in archive exfat-fuse/squeeze-backports uptodate 0.9.7-1~bpo60+1 exfat-utils/squeeze-backports uptodate 0.9.7-1~bpo60+1 google-chrome-stable/stable upgradeable from 27.0.1453.110-r202711 to 28.0.1500.63-r208724 ibus-mozc/squeeze-backports uptodate 1.2.855.102+main-1~bpo60+1 jd/squeeze-backports uptodate 1:2.8.5-120826-2~bpo60+1 linux-source/squeeze-backports uptodate 3.2+46~bpo60+1 linux-source-3.2/squeeze-backports uptodate 3.2.46-1~bpo60+1 mozc-server/squeeze-backports uptodate 1.2.855.102+main-1~bpo60+1 mozc-utils-gui/squeeze-backports uptodate 1.2.855.102+main-1~bpo60+1 unzip 6.0-4ubuntu1 newer than version in archive
