Examine source code of Amazon Smile Redirector

{
  "manifest_version": 2,
  "name": "Amazon Smile Redirect",
  "author": "nitrohorse",
  "short_name": "amazon-smile-redirect",
  "version": "1.3resigned1",
  "description": "Redirects Amazon.com, Amazon.de, and Amazon.co.uk links to Smile.Amazon.* so that you don't forget to contribute to your favorite non-profit ❤ \n\nFree and open-source.",
  "icons": {
    "64": "icons/icon-64.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.amazon.com/*",
        "https://www.amazon.de/*",
        "https://www.amazon.co.uk/*"
      ],
      "run_at": "document_start",
      "js": [
        "content_scripts/redirect.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{99c84242-25ec-4ffe-abad-a6643ff2cdd0}"
    }
  }
}