This is the only top element of a CopasiML file. It contains the models as well as the task information. We explicitedly allow the addition of elements which are not in the CopasiML name space so that this may be expandend by other user to suit their needs. This is only added to be backwards compatible by supporting the xsi:type mechanism, which is not needed for RelaxNG. This is only added to be backwards compatible by supporting the xsi:type mechanism, which is not needed for RelaxNG.