Examine source code of Runescape Cabbage

{
  "theme": {
    "images": {
      "theme_frame": "firefoxheadercabbage.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Runescape Cabbage",
  "manifest_version": 2,
  "description": "All images are the property of Jagex Ltd.\n\nJagex and RuneScape are registered trademarks of Jagex Limited\n\n<a href=\"https://outgoing.prod.mozaws.net/v1/46de9b519abb303a48ef2ec73bccb6a4a2c6611c2a3be3a3fe4aaec9a9f777d2/http%3A//www.RuneScape.com\" rel=\"nofollow\">http://www.RuneScape.com</a>"
}