D5 Render uses the Unreal® Engine. Unreal® is a trademark or registered trademark of Epic Games, Inc. in the United States of America and elsewhere. Unreal® Engine, Copyright 1998 – 2020, Epic Games, Inc. All rights reserved.
The Qt Project is licensed under the GNU Lesser General Public License v.3 ("LGPL"). In addition to LGPL, the Qt libraries are available also under commercial license terms from Digia. The Qt documentation is licensed under the GNU Free Documentation License version 1.3. D5 Render use Qt as LGPL, and you can get the source code https://code.qt.io/qt/qt5.git