magento-test/app/code/Magento/RemoteStorage/etc/adminhtml/system.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <section id="system">
            <group id="media_storage_configuration">
                <field id="media_storage">
                    <comment><![CDATA[<strong style="color:red">Warning!</strong> Database media storage will be ignored if remote storage is enabled.]]></comment>
                </field>
            </group>
        </section>
    </system>
</config>