$ git clone -n https://src.fedoraproject.org/rpms/plasma-vault.git /var/lib/mock/f42-build-side-1-3566281-46733/root/chroot_tmpdir/scmroot/plasma-vault
Cloning into '/var/lib/mock/f42-build-side-1-3566281-46733/root/chroot_tmpdir/scmroot/plasma-vault'...
$ git fetch origin 826369c9410e227d5f787b5b59d43218e34e8268:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-vault
 * [new ref]         826369c9410e227d5f787b5b59d43218e34e8268 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 826369c 6.4.0