$ git clone -n https://src.fedoraproject.org/rpms/mesa-demos.git /var/lib/mock/f40-build-2238292-53563/root/chroot_tmpdir/scmroot/mesa-demos
Cloning into '/var/lib/mock/f40-build-2238292-53563/root/chroot_tmpdir/scmroot/mesa-demos'...
$ git fetch origin 07845ceb992cd32cbb56a3894ce3d4461f13faf6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mesa-demos
 * [new ref]         07845ceb992cd32cbb56a3894ce3d4461f13faf6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 07845ce Split xdriinfo into its own package