The logo used in this website and in the extension comes from

https://commons.wikimedia.org/wiki/File:MW-Icon-CheckMark.svg

with the license

This work 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 2 of the License, or any later version. This work 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 version 2 and version 3 of the GNU General Public License for more details.

THIS LICENSE ONLY APPLIES TO THE LOGO (THE TICK) AND NOT TO THE REST OF THE WEBSITE, WHICH HAS ALL RIGHTS RESERVED.