The PCB is a double layer, with SMD components, mostly in 0805 sizes.
Some features of the PCB:
All GPIO Pins are clearly marked on the silkscreen.
The Logic level converters are (for this version at least) fixed to 3.3v on the LV side and 5v on the HV side. No additional power source is needed to use the converter. Logic level conversion is bi-directional, with a total of 8 channels.
The 3v LDO regulator can be powered from the 5v input, or directly from VIN, by changing the position of a jumper.
Additional Power ports (5v x 4), (3.3v x 4) and (GND x 8) is provided at the bottom of the PCB.
G1, and G2 are two separate bus connections, mainly put there to provide a way to connect various I2C devices together, but as these ports are not physically connected to anything else on the board, they can also be used for other purposes...