Examine source code of Amazon Shipping Filter

{
  "manifest_version": 2,
  "name": "Amazon Shipping Filter",
  "version": "0.1.4",
  "description": "Filter Amazon Listings Not Shipping to You.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.jp/*",
        "*://*.amazon.com/*",
        "*://*.amazon.in/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.it/*",
        "*://*.amazon.es/*",
        "*://*.amazon.de/*",
        "*://*.amazon.co.uk/*",
        "*://*.amazon.fr/*",
        "*://*.amazon.cn/*",
        "*://*.amazon.nl/*",
        "*://*.amazon.com.au/*",
        "*://*.amazon.com.sg/*",
        "*://*.amazon.com.mx/*",
        "*://*.amazon.com.br/*"
      ],
      "js": [
        "amazon-shipping-filter.js"
      ]
    }
  ]
}