nextcloud/lib/private/preview/markdown.php

<?php
/**
 * Copyright (c) 2013 Georg Ehrke georg@ownCloud.com
 * This file is licensed under the Affero General Public License version 3 or
 * later.
 * See the COPYING-README file.
 */
namespace OC\Preview;

class MarkDown extends TXT {
	/**
	 * {@inheritDoc}
	 */
	public function getMimeType() {
		return '/text\/(x-)?markdown/';
	}

}