This placeholder model for Pac-Man was found in the files of the current version of the game found online. Internally, it was dubbed "pico". Due to the original model not being renderable properly, it was ported over to Blender.
Several concepts of the characters and some of their expressions have been dumped online and put here. This is one of them. This is most likely based off of the placeholder model.
An updated version of the concept above was also leaked online by a group by the name of COPE, a group of six individuals known for also leaking other cancelled games and some of their builds. Apparently, this concept was said to be another concept made from the one above that had a more "proper" design. SaL, the leader of COPE, does not want to state the concept's origin.