Get Window Class Name by process id
The first thing to do is open the location of the program on the command line:
cd $path_to_exe
Then enter the name of the file followed by the parameter:
C:\Users\Users\source\repos\WindowClassNames\x64\Debug>WindowClassNames 8948
Result: Process id - 8948 windowName - Qt5QWindowPopupDropShadowSaveBits