Examine source code of Window Three

{
  "theme": {
    "images": {
      "theme_frame": "WindowThreeFirefox.jpg"
    },
    "colors": {
      "frame": "#dbdbdb",
      "tab_background_text": "#050505"
    }
  },
  "version": "2.0",
  "name": "Window Three",
  "manifest_version": 2,
  "description": "Persona for <a href=\"https://outgoing.prod.mozaws.net/v1/b3b019a23bdc0a261e2fe32f5765855679d0fc46d5a05f48ab1a485843b28027/http%3A//windowthree.com\" rel=\"nofollow\">windowthree.com</a>"
}