alt Hacker NewsIt's a black bishop, but not necessarily a dark-squared bishop. Both the black side and white side in a normal chess game get a dark-squared and a light-squared bishop, and I don't see anywhere that specifies which type this one is. It can be either one depending on where you place it.
Also if you care that much just mirror the solution horizontally or vertically, and now your bishop is on the white square instead.