Examine source code of Ricardo.gr

{
  "theme": {
    "images": {
      "theme_frame": "skin_top.png"
    },
    "colors": {
      "frame": "#d4d4d4",
      "tab_background_text": "#333333"
    }
  },
  "version": "2.0",
  "name": "Ricardo.gr",
  "manifest_version": 2,
  "description": "The official Firefox skin of <a href=\"https://outgoing.prod.mozaws.net/v1/8b4bca6ae3f8890a64dda727a8f6de481ec6966d59d02dbe92f629951b271bd1/http%3A//Ricardo.gr\" rel=\"nofollow\">Ricardo.gr</a>"
}