$ git clone -n https://src.fedoraproject.org/rpms/moditect.git /var/lib/mock/f39-build-2103927-50563/root/chroot_tmpdir/scmroot/moditect
Cloning into '/var/lib/mock/f39-build-2103927-50563/root/chroot_tmpdir/scmroot/moditect'...
$ git fetch origin 5921b1a86d9d855d3d25772f341ad092d002fe77:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/moditect
 * [new ref]         5921b1a86d9d855d3d25772f341ad092d002fe77 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5921b1a Rebuild