Examine source code of Perpetual FullScreen

{
  "manifest_version": 2,
  "name": "Perpetual FullScreen",
  "short_name": "Perpetual FS",
  "description": "Checking if it is open in full screen mode or not, and if it is not open, then it switches to full screen mode",
  "author": "HideClone",
  "version": "1.0.0",
  "icons": {
    "128": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ]
}