$ git clone -n https://src.fedoraproject.org/rpms/mlpack.git /var/lib/mock/f40-build-746386-112595/root/chroot_tmpdir/scmroot/mlpack
Cloning into '/var/lib/mock/f40-build-746386-112595/root/chroot_tmpdir/scmroot/mlpack'...
$ git fetch origin a7633def4cd24634d10332c0494afda97f68fc6e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mlpack
 * [new ref]         a7633def4cd24634d10332c0494afda97f68fc6e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a7633de Use RPM macros