When working with electronics, you generally start out with a
rats nest of wires breadboard, then after the requisite amount of fiddling with your design, transfer it to something more permanent. This can mean a printed circuit board (PCB) designed and manufactured for the task. If you’re only making one or two of your designs, or if you want it right now, you can instead transfer things to a solderable breadboard.
These have a lot of advantages, like not having to wait, and the fact that you can make modifications to them if you really have to. However, transferring components from your breadboard to these PCBs can be frustrating since the layout is generally different.
To ease this frustration, these PCBs come in the shape of a breadboard. This isn’t an entirely new idea by itself, besides fulfilling this useful form factor, these boards have a few other tricks. These include support for power supplies, SO08 pacakges, and, in the case of the full and half size board, pins are spaced so they can accommodate the Raspberry Pi’s GPIO connector.