An icon from icon theme <a href="//commons.wikimedia.org/wiki/Category:Crystal_Project" title="Category:Crystal Project">Crystal Project</a>;
<a href="https://en.wikipedia.org/wiki/Everaldo_Coelho" class="extiw" title="w:Everaldo Coelho">Everaldo Coelho</a> (<a rel="nofollow" class="external text" href="http://www.yellowicon.com">YellowIcon</a>);
LGPL
<a rel="nofollow" class="external text" href="https://store.kde.org/p/1002590/">All Crystal icons were posted by the author as LGPL on kde-look</a>;