I just sent a lengthy email into the Debian bug tracking system. I originally tried to send it directly to the developers through an already “closed” bug (which was returned undeliverable) so I sent it again to email@example.com. I sent it with the proper headings (I hope) so that it would get to the developers. the subject was “VRMS-Why is the Tango Icon theme listed as non-free”, and the project in question is vrms or (Virtual Richard M. Stallman) which is a program that will analyze the set of currently-installed packages on a Debian-based system, and report all of the packages from the non-free tree which are currently installed.
The entire email can be read here