Examine source code of Audio Paneer

{
  "manifest_version": 2,
  "name": "Audio Paneer",
  "version": "1.3",
  "description": "Allows panning audio between left and right channels using a slider.",
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a3cb26ce-0206-4065-9fbe-05445a2732f6}"
    }
  }
}