nextcloud-server/apps/theming/templates/settings-admin.php

<?php
/** @var array $_ */
/** @var OC_L10N $l */
script('theming', 'settings-admin');
style('theming', 'settings-admin')
?>
<div id="ncTheming" class="section">
	<h2><?php p($l->t('Theming')); ?></h2>
        Hello World
</div>