$ git clone -n https://src.fedoraproject.org/rpms/python-mailmerge.git /var/lib/mock/f45-build-31458-652/root/chroot_tmpdir/scmroot/python-mailmerge
Cloning into '/var/lib/mock/f45-build-31458-652/root/chroot_tmpdir/scmroot/python-mailmerge'...
$ git fetch origin c4055ef47ef1c6e5d98eb0e39f80dbdb88bd58c7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-mailmerge
 * [new ref]         c4055ef47ef1c6e5d98eb0e39f80dbdb88bd58c7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c4055ef Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild