Examine source code of Super Car Wallpaper

{
  "manifest_version": 2,
  "name": "Super Car Wallpaper Downloader",
  "version": "1.0",
  "description": "An addon that allows you to download supercar wallpapers.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "downloads"
  ],
  "browser_action": {
    "default_title": "Super Car Wallpaper Downloader",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{243731df-8d1d-4872-a4fa-11dae98a5c67}"
    }
  }
}