Some newer Audi (and other manufacturer) vehicles comes with nut inserts for China/Japan license plates that are too wide to accommodate bolts for US license plates. If the manufacturer does not provide an adapter then the dealer will screw directly into the bumper to attach a front license plate. This adapter uses two M6 cap screws, two 1/4x20 bolts, and two 1/4x20 acorn nuts to attach a US license plate to the built-in threaded inserts.
Parts I used for my installation:
Use the nuts to pull the bolts into the hex and seat them fully before assembling onto the car as they are an interference fit.
Print and use at your own risk and per your vehicle manual guidelines or local government regulations. I recommend the use of stainless steel hardware to avoid corrosion issues. You could swap the bolts and acorn nuts for pan head bolts/screws and regular nuts if you prefer a slim profile. I did not because I was worried about the thread end digging into the bumper.
Recommend to print in ASA, PC, or other exterior and UV resistant material.
Credit to this post for helping me sort out many of the dimensions to create this part: https://www.audiworld.com/forums/a4-allroad-b9-platform-discussion-216/front-license-plate-bracket-3058340/
The author marked this model as their own original creation.