Examine source code of CurrencyConverter

{
  "manifest_version": 2,
  "name": "CurrencyConverter",
  "version": "1.0",
  "description": "Quickly convert currencies right from your browser.",
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0138655f-0069-42e5-bf84-4f04be2ec8ba}"
    }
  }
}