$ git clone -n https://src.fedoraproject.org/rpms/mapnik.git /var/lib/mock/f41-build-858830-168485/root/chroot_tmpdir/scmroot/mapnik
Cloning into '/var/lib/mock/f41-build-858830-168485/root/chroot_tmpdir/scmroot/mapnik'...
$ git fetch origin dc9feb5d4ddde79411e3708388af87f7568aaecd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mapnik
 * [new ref]         dc9feb5d4ddde79411e3708388af87f7568aaecd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc9feb5 Update to 4.0.2 upstream release