Examine source code of Spin the World

{
  "theme": {
    "images": {
      "theme_frame": "Firefox_Persona.jpg"
    },
    "colors": {
      "frame": "#5e5e5e",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Spin the World",
  "manifest_version": 2,
  "description": "Firefox persona for the web game Spin the World, developed by KDU.\n\n<a href=\"https://outgoing.prod.mozaws.net/v1/f5b34e3e195b32e6e29cdf6da850081b403593eb81af6c2f545992f031fc0d9b/https%3A//kdugames.wordpress.com/\" rel=\"nofollow\">https://kdugames.wordpress.com/</a>"
}