[
  {
    "namespace": "manifest",
    "types": [
      {
        "id": "WidgetSize",
        "type": "string",
        "enum": ["small", "medium", "large"]
      },
      {
        "id": "BuiltinWidget",
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "page": {
            "$ref": "ExtensionURL",
            "description": "Path to the widget content."
          },
          "sizes": {
            "type": "array",
            "minItems": 1,
            "items": {
              "$ref": "WidgetSize"
            },
            "description": "Sizes the widget can be displayed at."
          },
          "default_size": {
            "$ref": "WidgetSize",
            "optional": true,
            "description": "Size the widget is displayed at until one is chosen. Defaults to the first of sizes."
          },
          "pref_branch": {
            "type": "string",
            "optional": true,
            "pattern": "^[A-Za-z][\\w-]*(\\.[\\w-]+)*$",
            "description": "Pref branch that stores whether the widget is enabled and the size chosen for it, in <pref_branch>.enabled and <pref_branch>.size."
          }
        }
      },
      {
        "$extend": "WebExtensionManifest",
        "properties": {
          "builtin_widget": {
            "$ref": "BuiltinWidget",
            "optional": true,
            "privileged": true,
            "description": "Declares a widget provided by a privileged extension."
          }
        }
      }
    ]
  }
]