This is a replacement back panel for top-loading models of the NES (aka NES-101). This design is to be used when installing an AV or NESRGB mod that uses a Nintendo style Multiout. This model is based on Greg Collin's back panel and has been remixed to include a spot for the physical palette switch.

The original panel can be found at:

https://www.retrorgb.com/nes-toploader-replacement-rear-panels.html