$ git clone -n https://src.fedoraproject.org/rpms/aggregate6.git /var/lib/mock/f39-build-1508413-35375/root/chroot_tmpdir/scmroot/aggregate6
Cloning into '/var/lib/mock/f39-build-1508413-35375/root/chroot_tmpdir/scmroot/aggregate6'...
$ git fetch origin 394280e0c1725f7e2022783bb6d2ac67dda065d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/aggregate6
 * [new ref]         394280e0c1725f7e2022783bb6d2ac67dda065d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 394280e Initial import