Examine source code of UrbanFirefox - Green

{
  "theme": {
    "images": {
      "theme_frame": "head_urban_green.jpg"
    },
    "colors": {
      "frame": "#55ff00",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "UrbanFirefox - Green",
  "manifest_version": 2,
  "description": "Urban Firefox [green version] \nCreator <a href=\"https://outgoing.prod.mozaws.net/v1/1ef1d3b86735afdde7921e635511879840344248b39f3e24a47f41cd31a1380f/http%3A//twitter.com/willskz\" rel=\"nofollow\">http://twitter.com/willskz</a>\nWait for some new versions!"
}