The Proto Featherwing is fairly simple. It's 2.0" x 0.9" so it fits right over a feather.
On the outer edge are all the pins you'd want to solder in to connect to the Feather. The inner set of pins are boxed and have small text or dots to indicate they are connected. The above shows the outer and inner set of pins. They are tied together so you have access to each I/O pin!
You also have two strips of holes that are all connected for 3.3V (left strip) and GND (right strip). This way you have plenty of power/ground connections available. The holes are 0.047" diameter and are connected with 24mil traces.