Seems like this stuff maybe comes and goes— like here's a repair guide for a 2010-vintage MBP which definitely shows all the connectors being right on the logic board:

https://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Logic+Board...

Doesn’t appear to be the case on the 16” MBP: https://www.ifixit.com/Teardown/MacBook+Pro+16-Inch+2019+Tea...

Looking at this photo from that page it appears that they are: https://guide-images.cdn.ifixit.com/igi/uavG2A3vFrVmwv6J.hug...

You can see the ports still in place after the motherboard has been removed.

Interesting, didn’t notice that. It looked like the logic board went all the way to the edges.