The idea originates from a discussion between Mickael Scherrer, Ralph and I on
Friday evening. Could we track all the files in every packages in the
distribution?

Ideally, this would allow us to investigate questions like:
 - How many copies of the GPL license are shipped?
 - How many GPL license still ship the old FSF address?
 - How many copies of jquery or md5.c?
 - How many files changed between two releases?