GoJs BPMN editor JSON explanation

We are in evaluation phase of GoJs software. Could you please provide me the explanation for the each element in JSON template provided for BPMN editor with GoJS? This is required for us to convert GoJs JSON to BPMN compatible JSON?

The complete implementation of the BPMN sample is provided in the extensions directory. You will need to read the code, including the comments, to understand how the app works.

If you have a specific question, we might be able to give you a more specific answer.