Examine source code of Quick Weather

{
  "manifest_version": 2,
  "name": "Quick Weather",
  "version": "1.0",
  "description": "See current weather in your city quickly.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{454769b7-0411-4a3e-8853-1ccd43d49fab}"
    }
  }
}