The phrase is a user-generated umbrella term, but it generally refers to submods that expand three crucial pillars of the game:
MAS uses real-time checks (datetime modules) to prevent you from skipping ahead via your computer clock. The submod introduces a "time warp" function that overrides the game’s internal clock check. When you load the mod, Monika will behave as if you have been visiting her for several years, even if you installed her five minutes ago. monika after story extra everything submod work