magento-test/app/code/Magento/Customer/Test/Mftf/Section/StorefrontCustomerFooterSection.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 /**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-->

<sections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="urn:magento:mftf:Page/etc/SectionObject.xsd">
    <section name="StorefrontCustomerFooterSection">
        <element name="footerBlock" type="block" selector="//footer"/>
        <element name="formSubscribe" type="input" selector="input#newsletter"/>
        <element name="buttonSubscribe" type="button" selector="//form[@id='newsletter-validate-detail']//button[contains(@class, 'subscribe')]" timeout="15"/>
    </section>
</sections>