Looks like Geos for the C64 has recently been reverse engineered and is now available on GitHub. https://en.wikipedia.org/wiki/GEOS_(8-bit_operating_system)#Rev

Looks like Geos for the C64 has recently been reverse engineered and is now available on GitHub. https://en.wikipedia.org/wiki/GEOS_(8-bit_operating_system)#Reverse_engineering_efforts https://en.wikipedia.org/wiki/GEOS_(8-bit_operating_system)#... https://github.com/mist64/geos https://github.com/mist64/geos