| Connection | Holder of read/write information |
| CustomTypes |
List of custom types stored in the data object and that must be serialized.
A custom type is e.g. a user implemented structure or catchment model. In order to store information on the custom type in the .m1dx file, the system needs to know which custom types are being used, and they must be added to this list. |
| ExtensionData | Holds data from an extended DataContract |