$ git clone -n https://src.fedoraproject.org/rpms/libmpeg2.git /var/lib/mock/f45-build-16609-488/root/chroot_tmpdir/scmroot/libmpeg2
Cloning into '/var/lib/mock/f45-build-16609-488/root/chroot_tmpdir/scmroot/libmpeg2'...
$ git fetch origin c5e0c730b10562d0bef650a9adf47a9d75c05b63:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libmpeg2
 * [new ref]         c5e0c730b10562d0bef650a9adf47a9d75c05b63 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c5e0c73 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild