Louis,
By default, the Memory window is opened so the debugger reads the memory to refresh that component.
In the command window, if you type "help" you will get some basic commands.
To retrieve memory content from the command window, the command to use is "DB Address".
DB stands for display byte I think.
READ_BD_BYTE is a MCU hardware command. It is not the same as the CW one because CW and/or the debug cable can also refresh other locations in the same time.
The way to send very low level commands like READ_BD_BYTE is either to create your own cable, or use for instance the TBDML (see dedicated board) where you have access to the full cable firmware.
BD must mean Background Debug.
What do you mean by "Register relocation" ?
Cheers,
Alban.