References to Street Fighter characters Ryu and Ken have been discovered in the Sega Saturn exclusive Fighters Megamix.
The discovery was made by @memory_fallen, who specialises in reverse-engineering Saturn games and coming up with cool hacks and patches to unlock hidden features.
Here's @memory_fallen to explain:
The strings
RYUandKENeach appear twice in the game data. At first I thought they were just initials for a high score screen, but upon further inspection, they are referenced by the Book Keep function.
Look who else is in the same neighborhood: Aoi from Virtua Fighter 3! Janet uses some of Aoi’s moves, so maybe she replaced Aoi?
I’m reasonably certain that these characters aren’t present on the disc and playable. But it’s interesting that they seem to have been considered!
Previously unknown cheat codes have also been found which allow you to unlock bonus features within the game (this process normally takes around 500 rounds), and there's also a hidden "BACKUP DEBUGGER", just like the one seen in the Saturn port of Fighting Vipers. You can also play as the game's training dummy.
You can read a full write-up of the findings here.