I tried to search for flyback diodes and I did not find anything that directly answers my question. Are there flyback diodes included on this board?
I did find the following info from user dc42(forum.arduino.cc/index.php?topic=115481.0 → reply #6):
If you are using a single mosfet to control a motor, then the body diode of the mosfet is in the wrong position in the circuit to act as a flyback diode, and you definitely need an external one. However, in a mosfet H-bridge configuration, the body diode of each mosfet acts a a flyback diode when the other mosfet in the same half of the H turns off, so you don’t normally need separate flyback diodes.
If you are using PWM and there is a lot of flyback energy coming out of the motor, then a Schottky flyback diode is best, because it will run cooler. Otherwise, use a silicon fast recovery diode. If you are not using PWM, and ordinary silicon rectifier diode is OK.
So… the “not normally” is somewhat ambiguous. From the design docs I have been reading they talk about making sure you have the flyback diodes, and this board at first glance does not have them.