
The bottom of these files mention "Raspbian 6.3", a variant of the Raspberry Pi OS. In addition, there are some separate ELF files for the games. On the 82 builds, however, there are 15 total ROMs (many of which are not accessible on the actual machines):

In the 82 builds, the ROMs included are only the ones for their specific menu.

As such, they are basically ROM dumps of the entire machines and feature notable unused elements, as seen below. In the Arcade1UP firmware updates, all of the data is intact including the games, menu system, and various other elements of code. In attempt to make up for the drastic issue, Arcade1UP not only took down and recompiled the updates, but also added the ability to play the much-desired "speed-up chip" version of Ms.
RETRO MS PACMAN GAME UPDATE
On the "Head-to-Head" model in particular, installing the update would cause the screen to display in horizontal resolution meaning, on the machine's vertical monitor, the games would play 90 degrees on their side. Arcade1UP attempted to fix the issues via downloadable firmware updates.which made things much, much worse. Pac-Man Arcade1UPs were first released, they.had some issues, to say the least.

It can likely be enabled by holding down 1P and 2P buttons while turning the machine on, but this is still not confirmed.
