In accordance with Qt's LGPL licensing, I am required to provide you with the source code used by the Qt libraries that UnoArduSIm.exe (dynamically) links to. You would only need their source code if you wished to change and rebuild the linked Qt DLL's to modify their functionality. So here are the Google Drive links where you can find a zip of the Qt source code used in the Qt V5.5.1 librraries (for UnoArduSim.exe V2.0 through V2.1.1) or the V5.6.2 libraries (UnoArduSIm.exe V2.2) links to.
Qt5.5.1:
https://drive.google.com/file/d/1hlqBlJHzDUp-3PkFBMQ2np_-llXqO2Y6/view?usp=sharing
Qt5.6.2:
https://drive.google.com/file/d/1B3AZWul7mHtDcGL1SjTLqN7i1fTiHbCi/view?usp=sharing
The full Qt V5.5.1 or V5.6.2 repositories can be found at
http://code.qt.io/cgit/