Examine source code of The Pubcrawlers

{
  "theme": {
    "images": {
      "theme_frame": "persona1.jpg"
    },
    "colors": {
      "frame": "#7d7d7d",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "The Pubcrawlers",
  "manifest_version": 2,
  "description": "Support The Pubcrawlers!\n<a href=\"https://outgoing.prod.mozaws.net/v1/c3eaca321db9ddf51684e05441e9ec16c3b4ee24af6d6f7d8e25d46c213a3e29/http%3A//www.the-pubcrawlers.com\" rel=\"nofollow\">www.the-pubcrawlers.com</a>"
}