[filterfish]

Looking up the binary in the package management system would also provide another source of useful information. Of course this would dramatically increase the complexity but would, I think, be useful.

If you could look it up using APT/dpkg first, that would be lovely :-)

[ajb]

If you have its path, dpkg already has an option to do that: "dpkg -S". Although some extra logic is needed for symlinks.