Examine source code of Clone the Tab

{
  "description": "Clone the active Tab",
  "manifest_version": 2,
  "name": "Clone the Tab",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "32": "icon32.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_title": "Clone the tab",
    "default_icon": {
      "32": "icon32.png"
    }
  },
  "version": "1.4",
  "applications": {
    "gecko": {
      "strict_min_version": "57.0a1",
      "id": "{80892737-292f-4bb0-b241-96b1dce30102}"
    }
  },
  "commands": {
    "execute": {
      "suggested_key": {
        "default": "Ctrl+Alt+D",
        "linux": "Ctrl+Alt+D"
      },
      "description": "Clone/Duplicate the tab"
    }
  }
}