Man, I wish I had known about this before! nmudiff is a program to email an NMU diff to the Debian Bug Tracking System. I often make quick little changes to debian packages to fix bugs or typos, and it's always been a bit of a pain to generate a patch to send to the maintainer. nmudiff uses debdiff (another very useful command I just learned about) to generate the patch, and email it to the bug tracking system with the appropriate tags.