Examine source code of Youtube Piped redirect

{
  "name": "Youtube redirect",
  "description": "Redirects (some of) youtube links to alternative frontends",
  "version": "1.2.1",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{6f2d31bc-4639-4e04-b3a2-4f4f010b8186}"
    }
  },
  "background": {
    "scripts": [
      "redirectListener.js"
    ]
  },
  "icons": {
    "48": "icon.jpeg"
  },
  "browser_action": {
    "default_icon": "icon.jpeg",
    "default_title": "Youtube redirect",
    "default_popup": "popup.html"
  },
  "permissions": [
    "*://www.youtube.com/*",
    "*://m.youtube.com/*",
    "webRequest",
    "webRequestBlocking",
    "storage"
  ]
}