$ git clone -n https://src.fedoraproject.org/rpms/luajit.git /var/lib/mock/f39-build-2505464-61701/root/chroot_tmpdir/scmroot/luajit
Cloning into '/var/lib/mock/f39-build-2505464-61701/root/chroot_tmpdir/scmroot/luajit'...
$ git fetch origin 3f3aab3ba899618babaa36073c5c90fd88f4f20e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/luajit
 * [new ref]         3f3aab3ba899618babaa36073c5c90fd88f4f20e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f3aab3 Update to version 2.1.1707061634