This is a bracket for fork blades of 34mm diameter. It is like a rear light bracket with small modifications. It uses the same bolts and nuts (M5) with generic brackets. This is the left mount; to print a right just use mirror feature in your slicer.
If you want to adapt it to your fork dimensions (or any other use) there is a public document on Onshape .
Also I have include clip for the stays of the fender. You can use the OpenSCAD file to modify the diameter of the holes.