To my great surprise I have not found an easy way to view the difference between locally altered configuration files in /etc from the defaults supplied in .deb for particular package.
Some day in future when debian/ubuntu will finally migrate to stateless /etc pushed by systemd it'll be trivial but now the closest I could find is 'debsums -ce'. Unfortunately it only reports the list of files, not an actual diff.
This is obviously tracked because on upgrade dpkg always asks what to do with altered configuration but how to get the set of diffs without upgrading?
