ELI5: Explain Like I'm 5

PCB reverse engineering

PCB Reverse Engineering is a process used to figure out the way a circuit board works. It is like taking a circuit board apart and looking at it, to see what wires are connected to what components and how they are connected, to understand how the board works and to make changes, if needed. This process is used by engineers to figure out how a certain circuit board is designed, so that they can create their own version that works better.