Razberry Pins

Hi all.
I am developing a plug in board to be able to use my RPI for some GPIO’s as well as the Razberry. The Razberry pluds into pins 1 to 10 which includes the I2C and Uart tx/rx pins. I have been gooling this but cant find if it uses both these comms

Not really a problem as there seems to be plenty of other pins available but trying to make the most out of the board