The Node class is part of the OpenDoc Utilities. They are a set of utilities developed by the OpenDoc team. ODF use internally a small portion of those utilities. Stuff we don't use are in the unused folder. Those classes and utilities are not part of the ODF project but they can be very useful. Your are free to use them. The maintenance and development of those utilities is done by the OpenDoc team. They are also available with the OpenDoc SDK.