What does it mean that schemas about knowledge itself?

Your epistemology — your theory of knowledge — is the meta-schema that governs all others.

Example: A software engineer insists that the only valid knowledge comes from controlled experiments and peer-reviewed studies. They dismiss a colleague's pattern-based intuition about system failures — intuition built from a decade of production incidents — because it 'isn't backed by data.' Their epistemology (only empirical evidence counts as knowledge) is silently filtering out an entire category of legitimate knowing. They don't realize they're running a filter. They think they're being rigorous.

Try this: Write down your answers to these four questions: (1) Can knowledge be certain, or is all knowledge provisional? (2) Is knowledge something you receive from authorities or something you construct through experience? (3) Is the world fundamentally simple and knowable, or complex and partially unknowable? (4) Can someone know something without being able to articulate why? Now read your four answers as a system. That system is your personal epistemology — the meta-schema governing every other schema you hold.