Welding melts the two parts together and usually adds in a third for extra filler.

Brazing basically just expands the pores of the metal of each part (simplifying here), and adds in a low-melt-temp material to fill the pores. The part cools, pores shrink, filler hardens, and it's all stuck together.

They use the camera to compensate for lack of visibility.

The downvotes would indicate folks didn't understand my comment. I'm not complaining or faulting anything in the design... but you can't just say "turn your head and use your eyes; don't depend on the camera!" Because your view is obscured by the design.

Most cars aren't built like they used to be. Windows are higher up and don't have the same amount of visibility since they crutch the camera. The back window is good for seeing headlights behind you while you drive, but it's a total blind spot in a parking lot.