$ git clone -n https://src.fedoraproject.org/rpms/mlton.git /var/lib/mock/f40-build-763353-122473/root/chroot_tmpdir/scmroot/mlton
Cloning into '/var/lib/mock/f40-build-763353-122473/root/chroot_tmpdir/scmroot/mlton'...
$ git fetch origin db0009940511ee1567b9acad90ede909a210a014:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mlton
 * [new ref]         db0009940511ee1567b9acad90ede909a210a014 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at db00099 Update to latest upstream release (rhbz#2243778)