Examine source code of Zing Price Checker

{
  "background": {
    "page": "background.html"
  },
  "content_scripts": [
    {
      "css": [
        "css/zing.css"
      ],
      "js": [
        "zing.js"
      ],
      "matches": [
        "http://www.amazon.com/*",
        "https://www.amazon.com/*",
        "http://www.amazon.co.uk/*",
        "https://www.amazon.co.uk/*",
        "http://www.amazon.de/*",
        "https://www.amazon.de/*",
        "http://www.amazon.fr/*",
        "https://www.amazon.fr/*",
        "http://www.amazon.es/*",
        "https://www.amazon.es/*",
        "http://www.amazon.it/*",
        "https://www.amazon.it/*",
        "http://www.amazon.nl/*",
        "https://www.amazon.nl/*",
        "http://smile.amazon.com/*",
        "https://smile.amazon.com/*",
        "http://smile.amazon.co.uk/*",
        "https://smile.amazon.co.uk/*",
        "http://smile.amazon.de/*",
        "https://smile.amazon.de/*",
        "http://smile.amazon.fr/*",
        "https://smile.amazon.fr/*",
        "http://smile.amazon.es/*",
        "https://smile.amazon.es/*",
        "http://smile.amazon.it/*",
        "https://smile.amazon.it/*",
        "http://smile.amazon.nl/*",
        "https://smile.amazon.nl/*",
        "https://www.zingprice.com/*"
      ]
    }
  ],
  "description": "Ensuring you always pay the lowest price by comparing Prices across Amazon's European stores.",
  "homepage_url": "https://www.zingprice.com",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "storage",
    "*://localhost/*",
    "*://www.amazon.co.uk/*",
    "*://www.amazon.de/*",
    "*://www.amazon.fr/*",
    "*://www.amazon.es/*",
    "*://www.amazon.it/*",
    "*://www.amazon.nl/*",
    "*://smile.amazon.co.uk/*",
    "*://smile.amazon.de/*",
    "*://smile.amazon.fr/*",
    "*://smile.amazon.es/*",
    "*://smile.amazon.it/*",
    "*://smile.amazon.nl/*",
    "https://zingprice.com/*",
    "https://www.zingprice.com/*"
  ],
  "manifest_version": 2,
  "name": "Zing Price Checker",
  "version": "1.1.0.2",
  "web_accessible_resources": [
    "images/cross.png",
    "images/return.png",
    "images/arrow-down.png",
    "images/arrow-left.png",
    "images/arrow-up.png",
    "css/zing.css",
    "tooltip.html",
    "images/loader.png",
    "images/de.png",
    "images/fr.png",
    "images/it.png",
    "images/es.png",
    "images/uk.png",
    "images/nl.png"
  ]
}