Some Fizik saddles have a clip in system. This mini-mudguard clips into this receptor.
As a mudguard this is of course not 100%, but it protects your behind from getting splashed with dirt. It has a small shield to protect the gap between saddle and saddlebag.
It matches a prusa mini printbed when printed diagonally and without rim.
PLA is probably the wrong choice, because it is rather brittle. I used PETG.
The fizik-clip.stl is provided if someone wants to design something else for this clip.
Pictures are from version v1.0.
v1.2: Updated the clip making it easier to insert it. Added a version text. Made the whole mudguard slightly smaller.
The author hasn't provided the model origin yet.