Test icons in the testdata folder are from either www.freepik.com or www.flaticon.com. They request any wedsite using these icons place the following in thei web pages:

<div>Icons made by <a href="http://www.freepik.com" title="Freepik">Freepik</a> from <a href="https://www.flaticon.com/" title="Flaticon">www.flaticon.com</a> is licensed by <a href="http://creativecommons.org/licenses/by/3.0/" title="Creative Commons BY 3.0" target="_blank">CC 3.0 BY</a></div>

<div>Icons made by <a href="https://www.flaticon.com/authors/flat-icons" title="Flat Icons">Flat Icons</a> from <a href="https://www.flaticon.com/" title="Flaticon">www.flaticon.com</a> is licensed by <a href="http://creativecommons.org/licenses/by/3.0/" title="Creative Commons BY 3.0" target="_blank">CC 3.0 BY</a></div>
