Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4769011.

So I went to install this on an MGN12 rail and discovered it does not work. The mounting holes must be different because there is not enough clearance between the hotend and the linear rail mounting holes. Since there was no step or f3d files I went ahead and reverse engineered the original design to give more space and allow this to work on a MGN12. I uploaded both the .stl and the f3d so that you can modify this for yourself. I followed the original design print settings and feel the pet-g is not a great option based on how thin this bracket is. You will want to either beef it up a bit or print in something more rigid like ABS. I hope this helps others and saves some time.