See bpmn-elements for supported elements. The engine only support elements and attributes included in the BPMN 2.0 scheme, but can be extended to understand other schemas and elements.
The aim is to, at least, have BPMN 2.0 core support.
This package is shipped with debug activated with environment variable
DEBUG=bpmn-engine:*. You can also provide your own logger.
A pretty image of a process
The bpmn-engine resides upon the excellent library bpmn-io/bpmn-moddle developed by bpmn.io
All diagrams are designed with Camunda modeler.