As per Issue #100 the relicensing of this package from GPLv3 to MIT was approved by the original developer of the Google2FA class (Phil) and the majority of the contributors, by contributions, of this package.
/**
* This program 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.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* PHP Google two-factor authentication module.
*
* See https://www.idontplaydarts.com/2011/07/google-totp-two-factor-authentication-for-php/
* for more details
*
* @author Phil
**/