Are you sure about the debian policy? Source package e2fsprogs builds to e2fsck-static, libcomerr2, comerr-dev, libss2, ss-dev, libuuid1, uuid-runtime, libuuid1-udeb, uuid-dev, libblkid1, libblkid1-udeb, libblkid-dev, e2fsprogs-udeb, e2fslibs, e2fslibs-dev, e2fsprogs, e2fsprogs-dbg, uuid-runtime-dbg, e2fslibs-dbg, libcomerr2-dbg, libss2-dbg, libblkid1-dbg, libuuid1-dbg and these are not virtual packages. General users who are using application manager have never heard about source packages, so they are not a concern here. For the rest 'apt-get source libss2-dbg' downloads correct source just fine. But I do agree that package naming should be consistent and reasonable. I just don't think that putting too strict automatic checks is a good idea.