The Leg Up Feet Support provides a nice step for those with short legs.
Not everyone is going to have legs long enough to easily climb onto a Yuba's integrated rack turned seat. As its name suggests, the Leg Up gives those with shorter legs (its designed for kids 4-7) a step to more easily clamber aboard. The bars can also be used as a foot rest if the stock Siderloader bars are too far away.
Compatible with only the Mundo cargo bike from Yuba, they easily mount to the frame with a 5mm allen key.