Examine source code of Weather App Extension

{
  "manifest_version": 2,
  "name": "Weather",
  "version": "1.0",
  "description": "Weather Extension",
  "icons": {
    "48": "images/48.png"
  },
  "browser_action": {
    "default_popup": "index.html"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{10cebeed-194a-4443-b4b0-f6848e1915a3}"
    }
  }
}