Knowledge is not justified, true belief. What is it?
David Deutsch has said that knowledge is, loosely speaking, useful information.
I propose, instead, to think of knowledge as problem-solving information.
Knowledge is information adapted to a purpose. In other words, it solves a problem.
Knowledge is information with the appearance of design (for a purpose). In other words, it solves a problem.
What kind of information is useful? Information which solves some problem worth solving.