As already [http://boxofstops.com/howitworks-action mentioned], the playing engine in Box Of Stops is written in the Python programming language. It is a rare example of an organ with a Pythonic Action.
Box Of Stops would like to credit the [https://mido.readthedocs.io/en/latest/ Mido] library that is an important moving part in this. Ole Martin Bjorndalen Bjørndalen (and a small team of contributors around him) have done a quality job here.