Examine source code of National Thanks

{
  "theme": {
    "images": {
      "theme_frame": "nt.firefox.header.jpg"
    },
    "colors": {
      "frame": "#949494",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "National Thanks",
  "manifest_version": 2,
  "description": "Show your support for allied troops and their families at <a href=\"https://outgoing.prod.mozaws.net/v1/8202f122de1671283a097a0ee8ec1ab1d50d23a834b26f3159f47e8d1ba84fae/http%3A//www.nationalthanks.com\" rel=\"nofollow\">http://www.nationalthanks.com</a> and with this custom Firefox theme. We've even styled it for easy tab viewing :) Thanks so much for showing your support!"
}