[
  {
    "namespace": "manifest",
    "types": [
      {
        "$extend": "WebExtensionManifest",
        "properties": {
          "devtools_page": {
            "$ref": "ExtensionURL",
            "optional": true
          }
        }
      },
      {
        "$extend": "Permission",
        "choices": [{
          "type": "string",
          "enum": [
            "devtools"
          ]
        }]
      }
    ]
  },
  {
    "namespace": "devtools",
    "permissions": ["devtools"],
    "allowedContexts": ["devtools", "devtools_only"],
    "defaultContexts": ["devtools", "devtools_only"]
  }
]