It’s got alligator cables and raw PCBs! What else can any self respecting geek want? Well, you can read all about it here:
It allows you to connect the GCW Zero to your computer and output the early boot messages to an external display, and also gives you control of the device through a terminal at the end of the booting processing.
Anyhow, it’s good to know you can do this. Yessiree.