Examine source code of Virtual Treeline

{
  "theme": {
    "images": {
      "theme_frame": "VirtualTreesHead.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Virtual Treeline",
  "manifest_version": 2,
  "description": "A 3D treeline created in a virtual world platform. This misty metaplace will bring a subtle bit of virtual nature to your Firfox browser. More info at <a href=\"https://outgoing.prod.mozaws.net/v1/8fd29b26c3406b1309a44f6cfcc9c34b1c87a3341ead70e04a8fa8b906cb3bec/http%3A//VideoHose.com\" rel=\"nofollow\">VideoHose.com</a>."
}