{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "required": [
    "key"
  ],
  "properties": {
    "key": {
      "type": "array",
      "description": "key is an array of values (though a single value is treated as a one-element array), to form a heirarchy. Using the first element of the key as the plugin name (e.g. [ 'summary' ]) is recommended. A key can either have children or a value, never both: parents are created and removed automatically.",
      "items": {
        "type": "string"
      }
    }
  }
}