Man, those two comments sound uncharitable. In the first paragraph Andy states:

> This guide assumes basic familiarity with spaced repetition systems.

The words "prompt"/"spaced repetition" are basic jargon for such systems.

But to make this comment at least a bit helpful, too: An example of a "prompt" in a spaced repetition system is the front of a flashcard. It's "spaced repetition" because you look at them multiple times, spaced out over time.