Examine source code of OutOfYoutube

{
  "manifest_version": 2,
  "name": "OutOfYoutube",
  "version": "1.1",
  "description": "Redirects youtube to a chosen link after some defined time.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "settings.html"
  },
  "permissions": [
    "tabs",
    "storage",
    "webNavigation",
    "*://*.youtube.com/*"
  ],
  "icons": {
    "48": "icons/new_icon.png"
  },
  "author": "LightStack",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "outOfYT.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "dev@outofyoutube.com"
    }
  }
}