server/apps/files_sharing/appinfo/app.php

<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Björn Schießle <bjoern@schiessle.org>
 * @author John Molakvoæ (skjnldsv) <skjnldsv@protonmail.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <robin@icewind.nl>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program. If not, see <http://www.gnu.org/licenses/>
 *
 */

use OCA\Files_Sharing\ShareBackend\File;
use OCA\Files_Sharing\ShareBackend\Folder;
use OCA\Files_Sharing\AppInfo\Application;

\OCA\Files_Sharing\Helper::registerHooks();

\OC\Share\Share::registerBackend('file', File::class);
\OC\Share\Share::registerBackend('folder', Folder::class, 'file');

\OC::$server->query(Application::class);