$ git clone -n https://src.fedoraproject.org/rpms/obs-service-tar_scm.git /var/lib/mock/f45-build-20425-570/root/chroot_tmpdir/scmroot/obs-service-tar_scm
Cloning into '/var/lib/mock/f45-build-20425-570/root/chroot_tmpdir/scmroot/obs-service-tar_scm'...
$ git fetch origin eec65eeaa3c2aa6882d94e9767e327ca170b7178:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/obs-service-tar_scm
 * [new ref]         eec65eeaa3c2aa6882d94e9767e327ca170b7178 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eec65ee Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild