>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3543659. --> Reported by: [justafish](https://www.drupal.org/user/161058) Related to !52 >>> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>When installing a module with Playwright, a config schema error is thrown</p> <pre>Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for editor.editor.xb_html_block with the following errors: 0 [settings.plugins.ckeditor5_list.properties] &lt;em&gt;ckeditor5_list&lt;/em&gt; is a required key. in Drupal\Core\Config\Development\ConfigSchemaChecker-&gt;onConfigSave() (line 98 of core/lib/Drupal/Core/Config/Development/ConfigSchemaChecker.php).</pre><p><img src="https://www.drupal.org/files/issues/2025-08-28/screenshot.png" alt=""></p> <h4 id="summary-steps-reproduce">Steps to reproduce</h4> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <h3 id="summary-remaining-tasks">Remaining tasks</h3> <h3 id="summary-ui-changes">User interface changes</h3> <h3 id="summary-api-changes">API changes</h3> <h3 id="summary-data-model-changes">Data model changes</h3>