Examine source code of APY Calculator

{
  "manifest_version": 2,
  "name": "APY Calculator",
  "version": "1.1",
  "description": "Use the APY calculator to work out the total interest and annual compounded interest rate on your investment or savings.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{39940343-fef8-4705-8fb2-ea77027843d3}"
    }
  }
}