This is just a simple clamp for your Sram Matchmaker brake. Brake only, no shifter attachment. Better than a zip tie.

In aluminum, these cost what? 20€ for a pair? And I'm not even interested in having my shifters and brakes in a single clamp anyways. Print these for 0.15€ a pair and save also 15g of weight in the process. :)

You need also:

M6x30mm screw and nut
OR
M5x30mm screw and nut

Print settings:

0.12-0.28 layer height
Your preferred material, PLA is ok.
Does not need supports, print as is.
4 walls, 4 bottom and top layers for almost full fill.