Examine source code of NG+GD

{
  "manifest_version": 2,
  "name": "NG+GD",
  "version": "1.0.1",
  "description": "Adds Geometry Dash functionality to the Newgrounds Audio Portal.",
  "icons": {
    "128": "ngplusgdlogo128.png"
  },
  "permissions": [
    "*://gdbrowser.com/api/*",
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.newgrounds.com/audio/listen/*"
      ],
      "js": [
        "NGplusGD.js"
      ]
    }
  ]
}