magento-test/app/code/Magento/Customer/Test/Mftf/Section/AdminCustomerAddressesDefaultBillingSection.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="AdminCustomerAddressesDefaultBillingSection">
        <element name="addressDetails" type="text" selector="//div[@class='customer-default-billing-address-content']//div[@class='address_details']"/>
        <element name="address" type="text" selector="//div[@class='customer-default-billing-address-content']//address//span"/>
        <element name="editButton" type="text" selector="//button[@data-index='edit_billing_address']"/>
    </section>
</sections>