It would be handy to somehow build metadata of from-git builds
- blocks of each contributing source
- where they were put in the source tree
- which VCS type they are from
- VCS url
- VCS branch (if applicable?)
- what the VCS revision was (git hash)
Putting a file into the actual source tarball would be tricky to do architecturally. Putting it in debian/ might be a possibility though.