In my experience there were plenty of both types of listings around (that is, both open BASIC listings and more inscrutable ML in DATA lines). My systems (PET a

In my experience there were plenty of both types of listings around (that is, both open BASIC listings and more inscrutable ML in DATA lines). My systems (PET and C64) had a built in disassembler, so it want necessarily that hard to comprehend the code anyway. And a lot of the DATA were just sprites and other graphics. Anyway, I learned a few things from those listings early on.