etc/config.xml
<?xml version="1.0"?>
<!--
~ SOZO Design Ltd
~
~ NOTICE OF LICENSE
~
~ This source file is subject to the Open Software License (OSL 3.0)
~ that is bundled with this package in the file LICENSE.
~ It is also available through the world-wide-web at this URL:
~ http://opensource.org/licenses/osl-3.0.php
~
~ @category SOZO Design Ltd
~ @package Sozo_CurrencyConversionExtended
~ @copyright Copyright (c) 2019 SOZO Design Ltd (https://sozodesign.com)
~ @license http://opensource.org/licenses/osl-3.0.php Open Software License (OSL 3.0)
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
<default>
<currency>
<currency_converter>
<api_key backend_model="Magento\Config\Model\Config\Backend\Encrypted"></api_key>
<timeout>100</timeout>
</currency_converter>
<open_rates>
<timeout>100</timeout>
</open_rates>
</currency>
</default>
</config>