You'll also need a USB cable for the above and/or a battery for portable use. Our demo code also uses a Relay FeatherWing and a NeoPixel Featherwing NeoPixel FeatherWing - 4x8 RGB LED Add-on For All Feather Boards A Feather board without ambition is a Feather board without FeatherWings!
1.9V and two ground pins. Two of the test points TM4 and TM5 connect to a pair of traces that looked suspiciously like a differential pair and probing them showed that TM4 was 0V and TM5 was 3.49V. These are the voltages found on the data lines of a USB cable and previous versions...