It's called schematics. There is a huge underground market for system board / chip / electrical level schematics for every single type of consumer electronics i

It's called schematics. There is a huge underground market for system board / chip / electrical level schematics for every single type of consumer electronics in China. Since schematics printed on paper, in a binder, etc are relatively easy to smuggle out of the factory (or make a duplicate for), it's most likely that the knockoffs use the manufacturing schematics at some point in their production. Bunny has a great post of the types of schematics available in shen zhen.