KDStateMachineEditor API Documentation  1.2.5
A framework for creating Qt State Machine metacode using a graphical user interface
Examples
Here is a list of all examples:

Klarälvdalens Datakonsult AB (KDAB)
"The Qt Experts"
https://www.kdab.com/
KDStateMachineEditor
Create Qt State Machine metacode using a graphical user interface
https://github.com/KDAB/KDStateMachineEditor