Sorry about the confusion. The documentation is fairly inadequate, and I apologise for that. The main reason for this is because the interface needs some improvements and should change soon.
The richest way to debug the ODrive is with the debugger, launched via the console or Eclipse.
Also supported is to read/write configuration, commands and errors from the ODrive over the USB. I just wrote some documentation for this, please see it on the ODriveFirmware readme.