Specify whether to include the part description.

The description text is obtained from the <wsdl:documentation> element found by the path:

wsdl:part/wsdl:documentation
However, when that description is absent, an alternative description may be used, which is searched for according to the settings in the nested parameter group.
In some WSDL files, all important descriptions (about web-service operations etc.) are found not in <wsdl:documentation> elements, but in annotations of XSD components (of the XML schema embedded in that WSDL), which define the data types of the WSDL message parts.

When that is used, it would be interesting to show those XSD annotations as descriptions of the message parts.

Nested Parameters:
Specify where an alternative description can be copied from.
See Also:
"Processing | Descriptions" parameter group, where you can specify how descriptions are processed and displayed.