Examine source code of Amazon Smile Redirector

{
  "manifest_version": 2,
  "name": "AmazonSmileRedirect",
  "version": "1.1.1",
  "description": "Redirects page from amazon.com to smile.amazon.com.",
  "icons": {
    "48": "icons/arrow-icon-svg.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.amazon.com/*",
        "*://www.amazon.co.uk/*",
        "*://www.amazon.de/*"
      ],
      "js": [
        "redirect.js"
      ]
    }
  ]
}