Examine source code of DPFirefox

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "DPFirefox",
  "manifest_version": 2,
  "description": "<a rel=\"nofollow\" href=\"https://addons.mozilla.org/de/developers/theme/dptb/\">https://addons.mozilla.org/de/developers/theme/dptb/</a>"
}