$ git clone -n https://src.fedoraproject.org/rpms/mailprocessing.git /var/lib/mock/f45-build-17951-506/root/chroot_tmpdir/scmroot/mailprocessing
Cloning into '/var/lib/mock/f45-build-17951-506/root/chroot_tmpdir/scmroot/mailprocessing'...
$ git fetch origin 7bfdd7f814010a7171b5f64b2d0b9d127b8594ae:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mailprocessing
 * [new ref]         7bfdd7f814010a7171b5f64b2d0b9d127b8594ae -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7bfdd7f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild