Compressing the tarball with xz -e instead of bzip2 would save about 12 MB, see http://thread.gmane.org/gmane.linux.redhat.fedora.devel/181336 and let me know if you'd like me to take care of this for devel.
I'm already repackaging main program sources to remove prohibited content, so no problem to compress the resulting package with xz instead of bzip2, I will do it. But additional catalog sources are provided directly from the developer and I prefer not to repackage them. I will, however, propose to the developer to use xz format.
Done in rawhide.