newsletter_subscriber_grid.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<layout xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/layout_generic.xsd">
    <update handle="formkey"/>
    <update handle="newsletter_subscriber_block"/>
    <container name="root">
        <block class="Magento\Backend\Block\Widget\Grid\Container" name="adminhtml.newsletter.subscriber.container" template="Magento_Backend::widget/grid/container/empty.phtml"/>
    </container>
</layout>