The USG is Good, not Bad
The USG is a firewall for your USB ports, protecting your computer from BadUSB. It connects between your computer and your untrusted USB device, isolating the badness and keeping your computer safe.
This is the firmware branch for the pre-assembled USG v1.0. If you want to build your own USG out of development boards, clone the v0.9 branch instead.
USG v1.0 hardware
The USG v1.0 is available now from the online store.