It’s essentially a merger of various forks — when developers take the source code of one piece of software and use it to develop something else — of FCE Ultra, a previous NES emulator. This means that ...

If you have a 3D printer and Raspberry Pi available, you could build a similar NES emulator yourself. But if you don’t have a 3D printer, but do have an original NES lying around, you could ...

in house – and [Morris] [krom] wanted to see if he could take the emulator on the SNES Classic Mini and run it on the Raspberry Pi. Yes, there are already SNES emulators on the Raspberry Pi.

As mentioned by the source, Nintendo has "often legally pursued emulator developers and ROM ... hundreds of the company's retro titles from the SNES, NES, N64 and handheld eras.