One of the new uma announced, also appears in the special anime for the anniv. Her name is Aston Machan, officially she is named after the Aston Hill and her owner Ma-chan. Aston Hill is where the founders of Aston Martin raced their self-built cars and eventually named their company after it.
Apparently her seemingly awareness of the 4th wall camera is a reference to the RL horse often stares at the cameras?