For what its worth the modified conffiles function will know if most of the files in /etc/lightdm/ modified except for /etc/lightdm/lightdm-gtk- greeter.conf which is not a lightdm conffile.
7:49:46 - flash:[~/photos/new/canon-xti/07-july] dpkg-query -W --showformat='${Conffiles}' lightdm /etc/lightdm/users.conf 8d76f0b67a0b6bf02464c2964deccdc9 /etc/pam.d/lightdm 02d4bd40eb6d8c03d4063da806aaf42c /etc/pam.d/lightdm-autologin 3d4f9d79e7302b4eff2b7a00e5e4693c /etc/init/lightdm.conf 7a30efa5ebebadd80fe78d21e8266588 /etc/dbus-1/system.d/org.freedesktop.DisplayManager.conf e2699292bde676d83e2985a61b7f80b5 /etc/lightdm/lightdm.conf 2c462cff90dda9d900add7187930ba00 obsolete /etc/lightdm/Xsession a7475cc7476a26be823c094c00f618c0 obsolete So if that file is important it'd be worthwhile to include it in the package hook or get it added as a conffile. ** Changed in: lightdm (Ubuntu) Status: New => Triaged -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/819954 Title: Lightdm package hook To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/819954/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs