Examine source code of URL Optimizer

{
  "manifest_version": 2,
  "name": "Amazon URL Cleaner",
  "version": "1.0",
  "description": "Automatically cleans Amazon URLs and their shortest form",
  "permissions": [
    "<all_urls>",
    "tabs",
    "webNavigation"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.com/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.co.uk/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{473e76bd-2c58-4d5e-a9a7-116f86f42718}"
    }
  }
}