For the Babboe Curve there is a maxicosi holder that vibrates quite a lot. In the picture you can see the marked 2 screws that are in the original product. The Block (Green in my case) prevents the base to from vibrations. You can still remove the maxicosi holder.
This one is to have an additional fixation that reduces the vibrations. I printed out of PLA with 100% infill to have the maximum strength. To fixate it drill a hole with 6mm drill in the spot of the hole. Then use a M5 screw and washers and of course locktight.
The author hasn't provided the model origin yet.