On deserialization stores any GXml.Node not used on this object, but exists in current XML file.
XML allows great flexibility, providing different ways to represent the same information. This is a problem when you try to deserialize them.
In order to deserialize correctly, you must create your XML, both by serializing a Serializable object or by hand writing. By using the former, you can add extra information, like nodes or contents in known nodes, but most of them could be ignored or lost on deserialization/serialization process. To avoid data lost, you can override get_enable_unknown_serializable_property method in order to return true, your implementation or the ones in GXml, will store all unknown properties and nodes on deserialization and must serialize again back to the XML file. Even you are allowed to get this unknown objects by iterating on Serializable.unknown_serializable_nodes hash table.
This property is ignored on serialisation.