Examine source code of General smart

{
  "theme": {
    "images": {
      "theme_frame": "cars_final.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "General smart",
  "manifest_version": 2,
  "description": "Dressing up your web browser can be almost as much fun as dressing up your smart car! Make your computer a little smarter with the latest smart Firefox Persona. Find out more about smart cars at <a href=\"https://outgoing.prod.mozaws.net/v1/59921d72c6b29ffb8a525857470fbbe01eaa59ffdcc39327b410f6962c9921c5/http%3A//www.thesmart.co.uk\" rel=\"nofollow\">www.thesmart.co.uk</a>"
}