magento-test/app/code/Magento/Backend/view/adminhtml/templates/widget/tabsleft.phtml

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
?>
<dl id="dl-<?= /* @noEscape */ $id ?>" class="accordion">
<?php foreach ($sections as $sectionId => $section) : ?>
    <dt id="dt-<?= /* @noEscape */ $id ?>-<?= /* @noEscape */ $sectionId ?>">
        <strong><?= $block->escapeHtml($section['title']) ?></strong>
    </dt>
    <dd id="dd-<?= /* @noEscape */ $id ?>-<?= /* @noEscape */ $section['id'] ?>" class="section-menu <?= !empty($section['active']) ? 'open' : '' ?>">
        <ul>
        <?php foreach ($section['children'] as $menuId => $menuItem) : ?>
            <li id="li-<?= /* @noEscape */ $id ?>-<?= /* @noEscape */ $sectionId ?>-<?= /* @noEscape */ $menuId ?>">
                <a href="#" title="<?= $block->escapeHtmlAttr($menuItem['title']) ?>">
                    <span><?= $block->escapeHtml($menuItem['label']) ?></span>
                </a>
            </li>
        <?php endforeach ?>
        </ul>
    </dd>
<?php endforeach ?>
</dl>