This is a simple storage tray for a 3DConnexion Spacemouse Pro for the IKEA Skadis workspace organizer system.
It uses these pegs (follow link, not my design), you will need 2 of these. They just snap fit into the back and work quite well.
I printed in Prusament PETG in 0.25mm Structural Mode. I recommend organic support for the slots on the rear side.
The author marked this model as their own original creation.