Examine source code of Total Google Sign Out

{
  "manifest_version": 2,
  "name": "Total Google Sign Out",
  "version": "6.0",
  "description": "Totally signs out of all Google Services",
  "content_scripts": [
    {
      "matches": [
        "*://accounts.google.com/*"
      ],
      "js": [
        "jquery-3.3.1.min.js",
        "background.js"
      ]
    }
  ]
}