Examine source code of Auto Smile

{
  "manifest_version": 2,
  "name": "Auto Smile",
  "version": "1.3resigned1",
  "description": "Never forget to use Amazon Smile again with Auto Smile!",
  "icons": {
    "48": "icon-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.amazon.com/*"
      ],
      "js": [
        "auto_smile.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{db450ce2-3135-4a5b-a8d5-7b5fd5bc3297}"
    }
  }
}