settings.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Text (on cohorts) - Settings
 *
 * @package   block_cohortspecifichtml
 * @copyright 2017 Kathrin Osswald, Ulm University kathrin.osswald@uni-ulm.de
 *            based on code from 2012 Aaron Barnes
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die;

if ($ADMIN->fulltree) {
    $settings->add(new admin_setting_configcheckbox('block_cohortspecifichtml_allowcssclasses',
            get_string('allowadditionalcssclasses', 'block_html'),
            get_string('configallowadditionalcssclasses', 'block_html'), 0));
}