It is a small storage box with a train picture on the front.
I added a mesh modifier to match my side baskets. I'm including the .stl and .3mf files.

Print instructions

I printed in filamentum PLA with .2 layer height and 15% rectilinear infill. Modifier has 20% gyroid with layer and perimeters of 0 bottom, 0 perimeter, 0 top.