Examine source code of Dark sportscar

{
  "theme": {
    "images": {
      "theme_frame": "sportscar.png"
    },
    "colors": {
      "frame": "#9c9c9c",
      "tab_background_text": "#9c9c9c"
    }
  },
  "version": "2.0",
  "name": "Dark sportscar",
  "manifest_version": 2,
  "description": "<a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/2bf98fdd40392a917f580802408fdc6cc92d41b0a59807b7a622ad4aadad7624/http%3A//www.twitter.com/loffern\">http://www.twitter.com/loffern</a>"
}