In Fedora Extras CVS mock/devel, the mock source tarball is a whopping 15 MiB in size $ du -h mock-0.6.5.tar.gz 15M mock-0.6.5.tar.gz because it includes the huge Anjuta 2 twice. As src.rpm and extracted into a sub-directory.
Additionally, the mock-0.6.5.tar.gz archive contains mock-0.6.3.tar.gz mock-0.6.4.tar.gz mock-0.6.5.tar.gz which is questionable, too.
Hrm, this seems to be how the upstream tarballs are being created, reassigning.
Cleaned up cruft in CVS sandbox and modified Makefile to do a clean before generating tarballs.