Specify whether to generate the Overview Frame, as shown on this diagram:
Overview Frame contains primary navigation lists (such as the lists of namespaces, WSDL files and XML schemas that have been documented).

That may be more important for big WSDL/XSD projects (with many WSDL files/schemas/namespaces). For a small XML schema or when you generate some specialized documentation, you may find that the Overview Frame is redundant.

Nested Parameters:

Control the Overview Frame content