I've bought a new bicycle lock and the only position left for its mount, where it wouldn't interfere with bags or other accessories, was on the downtube, right behind the front wheel. And to protect the code mechanism from flying dirt, I've designed this cap.
Depending on the adhesion of your printbed, you might want to print this using a brim. You'll definitely need (preferably organic) supports – see the attached screenshot.
When you lock your bike, simply re-seat the cap turned 180°, and it still allows the „arm“ to swivel.
PS: FreeCAD source file included.
The author marked this model as their own original creation.