newsupernova/app/code/Magefan/Blog/view/adminhtml/layout/blog_post_relatedpostsgrid.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © 2015 Ihor Vansach (ihor@magefan.com). All rights reserved.
 * See LICENSE.txt for license details (http://opensource.org/licenses/osl-3.0.php).
 *
 * Glory to Ukraine! Glory to the heroes!
 */
-->
<layout xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/layout_generic.xsd">
    <container name="root" label="Root">
        <block class="Magefan\Blog\Block\Adminhtml\Post\Edit\Tab\RelatedPosts" name="blog.post.edit.tab.relatedposts"/>
    </container>
</layout>