VRD/@@D -what are these ?

in TSTC - VRD and @@D are present.

But when you execute the transaction...Its not possible. The Description forVRD is that

@@D is that it calls a debugger documentation but if you try to execute the TCD there is no visible changes !

VRD - SD Generate data F.orders on Hand

What are these ? Shed more light,please !