newsupernova/vendor/magento/module-backend/view/adminhtml/templates/admin/overlay_popup.phtml

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

// @codingStandardsIgnoreFile

?>
<div class="wrapper-popup">
    <div class="middle" id="anchor-content">
        <div id="page:main-container">
        <?php if ($block->getChildHtml('left')): ?>
            <div class="columns <?= /* @escapeNotVerified */ $block->getContainerCssClass() ?>" id="page:container">
                <div id="page:left" class="side-col">
                    <?= $block->getChildHtml('left') ?>
                </div>
                <div class="main-col" id="content">
                    <div class="main-col-inner">
                        <div id="messages" class="messages" data-container-for="messages">
                            <?= $block->getLayout()->getMessagesBlock()->getGroupedHtml() ?>
                        </div>
                        <?= $block->getChildHtml('content') ?>
                    </div>
                </div>
            </div>
      <?php else: ?>
          <div id="messages" data-container-for="messages"><?= $block->getLayout()->getMessagesBlock()->getGroupedHtml() ?></div>
          <?= $block->getChildHtml('content') ?>
      <?php endif; ?>
         </div>
    </div>
    <?php if ($block->getChildHtml('footer')): ?>
    <div class="footer">
        <?= $block->getChildHtml('footer') ?>
    </div>
    <?php endif; ?>
    <?= $block->getChildHtml('js') ?>
</div>