I think you are referring to the fantasy console PICO-8 [1] which has "carts" that are games inside of a PNG container [2]. [1] https://www.lexaloffle.com/pico

I think you are referring to the fantasy console PICO-8 [1] which has "carts" that are games inside of a PNG container [2]. [1] https://www.lexaloffle.com/pico-8.php https://www.lexaloffle.com/pico-8.php [2] https://pico-8.fandom.com/wiki/P8PNGFileFormat https://pico-8.fandom.com/wiki/P8PNGFileFormat