Examine source code of DjVu Viewer

{
  "manifest_version": 2,
  "name": "DjVu Viewer",
  "version": "1.0",
  "description": "View DjVu files directly in your browser.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f17d2424-d57c-4843-a182-70ec6084d50e}"
    }
  }
}