Examine source code of VIEWTEST - Amazon Image Testing

{
  "manifest_version": 2,
  "name": "VIEWTEST - Amazon Image Testing Tool DEV",
  "description": "The testing tool will allow the user to enter their own product main picture and to see it as if it was selling on amazon.",
  "version": "4.4.2",
  "background": {
    "persistent": true,
    "scripts": [
      "js/jquery.min.js",
      "js/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/128.png"
  },
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png",
    "256": "icons/256.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.com/*",
        "*://*.amazon.de/*",
        "*://*.amazon.co.uk/*",
        "*://*.amazon.in/*",
        "*://*.amazon.it/*",
        "*://*.amazon.fr/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.co.jp/*",
        "*://*.amazon.es/*",
        "*://*.amazon.com.mx/*",
        "*://*.amazon.com.br/*",
        "*://*.amazon.com.au/*",
        "*://*.amazon.ae/*",
        "*://*.amazon.com.tr/*",
        "*://*.amazon.sg/*",
        "*://*.amazon.se/*"
      ],
      "js": [
        "js/jquery.min.js",
        "js/script.js",
        "js/mutations.js"
      ],
      "css": [
        "css/content_script.css",
        "css/devices.min.css",
        "css/phone-frame.css"
      ],
      "run_at": "document_end"
    },
    {
      "matches": [
        "*://*.viewtest.com/*",
        "http://localhost:3000/*"
      ],
      "js": [
        "js/script2.js"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "downloads",
    "*://www.amazon.com/",
    "*://localhost/",
    "https://viewtest.com/*",
    "webRequest",
    "webRequestBlocking",
    "webNavigation"
  ],
  "web_accessible_resources": [
    "popup.html",
    "product_popup.html",
    "poll.html",
    "checkout.html",
    "thanks.html",
    "images/*",
    "js/phone-controls.js"
  ],
  "content_security_policy": "script-src 'self' 'unsafe-eval' https://viewtest.us6.list-manage.com https://viewtest.com; https://www.google-analytics.com; object-src 'self'"
}