The Japanese video game industry developed a standard for connecting a video game motherboard to a cabinet. The JAMMA standard was a large board-edge connector that delivered power and coin/joystick/button inputs, and sent out composite video signals to a monitor.
Once the standard took hold, it was economically feasible to sell generic cabinets. Arcade operators could update, rotate, and install new titles without having to move heavy bulky plywood cabinets in and out of arcades.
These cabinets got the nickname "candy cabinets" for unknown reasons although it might be connected to an old SNK/NeoGeo line of cabinets.
The OP article explains that Japanese law said that these generic cabinets had to do something out of the box, probably to allow the purchaser to test the product. Sega and Taito created very cheap JAMMA motherboards that came preinstalled with a small game to do this. It was expected that this board would be tossed out immediately and a real game attached to the harness after that.
The little link there explains it. The board was included for free with the hardware so that you can confirm that it's working. But the arcade operator will immediately replace it with an actual game.
> In the 1990s, a big part of Sega’s arcade business was selling cabinets like the Astro City that didn’t come with game boards included. Dottori-kun seems to exist primarily to provide a simple game that could be used for assessment in line with [Japan’s Electrical Appliance and Material Control Law]. It was included with the cabinet as sold (likely because the cabinet had to be in the same state as assessed for it to be valid), but was not usable for an arcade operator beyond basic testing that the game board worked, it would just be thrown away or maybe saved to be scavenged for parts.
