This is a model for a portal axle style 3D printed gearbox for DIGILENT motors (https://export.farnell.com/digilent/290-006/dc-motor-12v-789rpm-1-19-gearbox/dp/2528804?st=robot ). It's a 3 reduction ratio and fits inside a bigger size RC wheel.
The author marked this model as their own original creation.