the function that feeds this data is compiled native code, basically the function that gets the data from the packet and parses it works statically meaning that it won't do more than what it is designed to do in the first place.... In simpler words it will only process the standard data ignoring the rest. Then it forwards to the "front end" unreal script functions that build the windows...
The function that parses the data is probably located in engine.dll, I would say good luck to you but.. well :)