qcow2-backing-qcow2-slice.json

protocol:
{
  "driver": "file",
  "filename": "/var/lib/libvirt/images/i.qcow2",
  "size": 4294967296
}

format:
{
  "driver": "qcow2",
  "file": "0123456789ABCDEF0123456789ABCDE",
  "size": 8589934590,
  "backing-file": "json:{\"driver\":\"raw\",\"offset\":1234,\"size\":5768,\"file\":{\"driver\":\"file\",\"filename\":\"/var/lib/libvirt/images/i.qcow2\"}}",
  "backing-fmt": "qcow2"
}