What you were guessing is correct, the DCT is used to hold configurations. These include mfg information, certificates for security and WIFI configurations. users can also add any application specific sections there.
To figure out what goes in DCT and how, have a look at WICED/platform/include/platform_dct.h. This includes the structure that goes in to the DCT. The file WICED/internal/dct.c creates an instant of this structure and fill it. This is finally created in to a binary file and written to internal or external flash.
Hope this would help.
I must admit that I get nervous when the only documentation is is the comments in the code files. (One reason I dislike doxygen!) Coders may well be able to write good code but my experience is that either the comments are missing, misleading or do not add any value at all.
While I admit that it is easy for code and documentation to get out of sync and I congratulate Broadcom for providing the code in the first place, I still like to see documentation that describes the philosophy, functionality and intended manner or use. Example code is generally useful but rarely added to comments.
However I guess we have to deal with what is available....