This is ARC A10-25 Motor Mount +1mm.
R142032 is designed for A10-25 to fit the 1.5mm aluminum chassis.
The new motor mount has extended the front lower end to have an extra lower pin that can fit on the chassis.
The chassis flex in the middle-front area can be fine-tuned more.
Due to the new 1.5mm chassis being lower than the carbon chassis and the motor will touch the ground when cornering.
So the new motor mount raised the motor height by 1.0mm and the chassis slot for the motor was also removed.