newsupernova/vendor/magento/module-theme/etc/events.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="theme_delete_before">
        <observer name="clean_theme_related_content" instance="Magento\Theme\Observer\CleanThemeRelatedContentObserver" />
    </event>
    <event name="theme_save_after">
        <observer name="check_theme_is_assigned" instance="Magento\Theme\Observer\CheckThemeIsAssignedObserver" />
    </event>
</config>