This is item #609600 from STOKKE®, the owner of the Babyzen Yoyo stroller line. One must have fallen out randomly and I reached out to them. $14 + $10 shipping + tax for these 2 tiny plastic items, so I decided to learn TinkerCAD and make my first model instead.
I printed it with 0.12mm + 4 walls + 50% infill using triangles because the first few versions would break when I tried to insert it into the plug. I also used slim tree supports. The 3mf has all of my print settings.
I gently pushed it in and it fit perfectly. And now the undercarriage storage canopy no longer drags on the ground.
The author marked this model as their own original creation.