Examine source code of youtube2invidious

{
  "manifest_version": 2,
  "name": "Invidious redirect",
  "description": "redirect automatically from Youtube links to Invidio.us",
  "permissions": [
    "*://*.youtube.com/*",
    "*://youtu.be/*"
  ],
  "background": {
    "scripts": [
      "redirect.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "redirect@invidious-youtube.com"
    }
  },
  "version": "1.0"
}