Ars Technica: We traced Namco’s “new” Pac-Man demake to its source: A 2008 fan ROMhack
Last month, Bandai Namco announced a special bonus for Switch players who invested in the new Namco Museum Archives Vol. 1. In addition to 10 emulated Namco classics, the game's official Nintendo store page notes it includes "a newly created 8-bit demastered version of Pac-Man Championship Edition" (emphasis added) [original emphasis maintained].
[..] As it turns out, though, the "newly created" part of the game's promotion isn't quite accurate. Bandai Namco has confirmed to Ars Technica that its much-lauded Championship Edition demake is actually based directly on an obscure NES/Famicom ROMhack created over a decade ago by a Japanese fan going by the handle Coke774.
"Throughout Pac-Man's 40-year history, he has inspired countless fans to take on game development as either a hobby or a career," the development team said in a statement provided to Ars Technica. "In the case of Coke774, his work was highly appreciated by our team and we worked with him officially to implement his design into our game."