You mean peel apart an 8- or perhaps even 10-layer board?

No, Rob. I mean how modules are grouped on a PCB, where high activity digital circuitry is arranged relative to connectors, how connectors and plugs look like, how their shields are 360° connected to chassis ground, how all internal modules like hard disks etc. are connected with screws to chassis ground, with how many screws PCB is connected to chassis ground, how input and output signals are filtered, protected and fused, ...

Good grounding technique is not a question of number of layers of PCB, but is a question of how to group everything on PCB and connect to chassis ground.

Kai