nextcloud/core/templates/installation_forbidden.php

<?php
/**
 * SPDX-FileCopyrightText: 2019 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */
?>
<div class="guest-box">
	<h2><?php p($l->t('Error')) ?></h2>
	<p class="text-left">
		<?php p($l->t('It looks like you are trying to reinstall your Nextcloud. However the file CAN_INSTALL is missing from your config directory. Please create the file CAN_INSTALL in your config folder to continue.')) ?>
	</p>
</div>