$ git clone -n https://src.fedoraproject.org/rpms/rubygem-test-unit-rr.git /var/lib/mock/f45-build-35379-695/root/chroot_tmpdir/scmroot/rubygem-test-unit-rr
Cloning into '/var/lib/mock/f45-build-35379-695/root/chroot_tmpdir/scmroot/rubygem-test-unit-rr'...
$ git fetch origin 1b5f4e4fa9544ee89e30763955d335fa6d8ecb84:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-test-unit-rr
 * [new ref]         1b5f4e4fa9544ee89e30763955d335fa6d8ecb84 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1b5f4e4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild