I doubt anyone is going to respond, so I'll just close this out.
I did find note 1816250 which has a README attached.
The General Enhancements section says:
Groupware profile was stored in the user profile folder on the client
machine in .xml file format as GWIConfigData.xml. This file is changed
to binary format and hence will be stored as GWIConfigData.bin
I don't like it nor do I understand why SAP would do this but at least it is documented.
NICK