Examine source code of addons.mozilla.org

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Header_AMO.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#303f45"
    }
  },
  "version": "2.0",
  "name": "addons.mozilla.org",
  "manifest_version": 2,
  "description": "addons.mozilla.org (AMO) is Mozilla's official site for add-ons for Mozilla applications. Add-ons let you add new features to Firefox, Thunderbird, SeaMonkey, and Sunbird. From AMO, you can browse and download thousands of add-ons to change the way you use the internet. "
}