$ git clone -n https://src.fedoraproject.org/rpms/plasma-sdk.git /var/lib/mock/f42-build-side-1-3578412-46814/root/chroot_tmpdir/scmroot/plasma-sdk
Cloning into '/var/lib/mock/f42-build-side-1-3578412-46814/root/chroot_tmpdir/scmroot/plasma-sdk'...
$ git fetch origin 64d686148d138ecae4be83bbea44202a21a8607c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-sdk
 * [new ref]         64d686148d138ecae4be83bbea44202a21a8607c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 64d6861 6.4.1