Checksum post processor (which artifact?)

The post-processors block below creates the artifacts shown here (, packer-qemu, and packer_qemu_md5.checksum). I’d like to have the checksum post processor run against rather than packer-qemu but I’m not finding a way to specify this. I suppose a workaround might involve using that second shell-local to do it but that seems even more kludgy given the checksum type being available.

How can I get the checksum for

/output>md5sum *
85a828b478997607c13462d46bef14aa  packer-qemu
94038bd8ff77549a155b1d883b06f18d  packer_qemu_md5.checksum

/output>cat packer_qemu_md5.checksum
85a828b478997607c13462d46bef14aa        packer-qemu
  "post-processors": [
      "inline": [
        "set -eu",
        "export _IMAGE=\"output/packer-qemu\"",
        "sudo qemu-img convert -f qcow2 -O qcow2 \"$_IMAGE\" \"$_IMAGE.convert\"",
        "sudo rm -rf \"$_IMAGE\"",
        "sudo chmod a+r /boot/vmlinuz*",
        "sudo virt-sysprep --operations defaults,-ssh-hostkeys,-ssh-userdir,-customize -a \"$_IMAGE.convert\"",
        "sudo virt-sparsify --in-place \"$_IMAGE.convert\"",
        "sudo qemu-img convert -f qcow2 -O qcow2 -c \"$_IMAGE.convert\" \"$_IMAGE\"",
        "sudo rm -rf \"$_IMAGE.convert\""
      "type": "shell-local"
      "compression_level": 9,
      "keep_input_artifact": false,
      "output": "output/",
      "provider_override": "libvirt",
      "type": "vagrant"
      "type": "checksum",
      "checksum_types": ["md5"],
      "output": "output/packer_{{.BuildName}}_{{.ChecksumType}}.checksum",
      "keep_input_artifact": true
      "inline": ["jq --arg checksum \"$(cat output/packer_qemu_md5.checksum | awk '{print $1}')\" '.versions[0].providers[0].checksum = $checksum' metadata.json > ../metadata.json"],
      "type": "shell-local"