Examine source code of Currency converter

{
  "manifest_version": 2,
  "name": "Currency converter",
  "version": "2.7resigned1",
  "description": "Currency converter allows you to convert among more than 150 currencies from around the world and cryptocurrencies like Bitcoin or Ethereum, using the Yahoo Finance service and Cryptonator.",
  "icons": {
    "32": "icons/cc-32.png",
    "48": "icons/cc-48.png",
    "64": "icons/cc-64.png",
    "96": "icons/cc-96.png"
  },
  "permissions": [
    "storage",
    "*://query.yahooapis.com/*",
    "*://api.cryptonator.com/*"
  ],
  "browser_action": {
    "default_icon": "icons/cc-32.png",
    "default_title": "Currency converter",
    "default_popup": "cc.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eb3b5752-c244-49a8-8dc8-f7838248e69e}"
    }
  }
}