On the top side of this green beast, there's not just the GoPro's shutter button. Also part of the team:

0.5" 72x32px OLED display (labeled OEL9E3033A0)

Seiko ML414H back-up battery

Another EMI shield and a thermal pad later, the bottom side isn't less exciting:

Qualcomm QCA9377 WiFi and Bluetooth chipset

Top-facing MEMS microphone