Examine source code of Auto Vagex

{
  "manifest_version": 2,
  "name": "autovagex",
  "version": "0.9.5",
  "description": "Automation helper for vagex manual viewing system.",
  "icons": {
    "16": "/icons/16.png",
    "48": "/icons/48.png",
    "128": "/icons/128.png"
  },
  "background": {
    "scripts": [
      "browser-polyfill.min.js",
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_popup": "/popup/menu.html",
    "default_icon": {
      "48": "/icons/48.png"
    }
  },
  "permissions": [
    "http://vagex.com/*",
    "https://vagex.com/*",
    "https://www.youtube.com/*",
    "storage",
    "webNavigation"
  ]
}