Examine source code of Shadow Unit

{
  "theme": {
    "images": {
      "theme_frame": "suffban.PNG"
    },
    "colors": {
      "frame": "#c0c0c0",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Shadow Unit",
  "manifest_version": 2,
  "description": "Based on Amanda Downum's art for the <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/26c68213647972c23d1a044c458ac65e569968fb36631a7559894ebd09a37e89/http%3A//shadowunit.org\">http://shadowunit.org</a> website."
}