The original idea for ModulaRPG was to have a ring-binder folder with the core rules, into which a setting and it's specific rules could be seamlessly fitted. The ring-binder concept also works as an analogy for computer software to insert setting / optional rule modules.
with this in mind, the core rules are designed to be as simple, generic and intuitive as possible, while still providing a skeleton for anything a GM needs for a fairly freeform - type game.