All the lovely rocking motion is kinda pointless if the decorative mobile keeps bashing the baby in the face. But insert this little adapter into the socket before inserting the mobile arm and you can move that dangling toy right back out of baby's eyes.
Caveat: If you're going to print something a stranger made to keep a toy from falling on your baby's face, you need to accept all responsibilities. I make no promises about its suitability to the task. You know you could just leave the mobile in the box, right? The rest of the rocker will still work without it. But if you decide to proceed anyway, I suggest printing with PET-G, in solid plastic. (100% infill, and 10 perimeter shells should pretty much do it.)
The author hasn't provided the model origin yet.