A BPMNDiagram element is generated in the BPMN file for each BPMN diagram. The ID consists of the BPMNDIAGRAM_ string and the GUID of the model.
This element always contains a BPMNPLane element with the bpmnElement attribute, whose value consists of the COLLABORATION_ string and the GUID of the model for a model of the BPMN collaboration diagram (BPMN 2.0) type and of the FLOWNODE_ string and the GUID of the subprocess for a model of type BPMN process diagram (BPMN 2.0).