Examine source code of TabsManager

{
  "manifest_version": 2,
  "name": "TabsManager",
  "version": "1.1.0",
  "description": "An add-on that manages tabs.",
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/icon-32.png",
    "default_title": "TabsManager",
    "default_popup": "src/main.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5466fb36-a619-4dae-b2ef-b58237e0668d}"
    }
  }
}