New T-Rex - Brake Mounts

can you give me a more detailed explanation, cos i cant figure it out in my head

There's less of the 4-bolt mount outside of the tubing. If you look at a lot of frames, the 4-bolt mounts are bought in and welded onto the exterior of the seat-stay. However, on here, they are sunken into the frame, so they're not on the exterior, which means there's more support around the brake because it's not so far out (works on lever principles).