Full Idea
Whereas Leibniz and Frege predicate apriority primarily of truths (or more fundamentally, proofs of truths), Kant predicates apriority primarily of cognition and the employment of representations.
Gist of Idea
Is apriority predicated mainly of truths and proofs, or of human cognition?
Source
Tyler Burge (Frege on Apriority (with ps) [2000], 1)
Book Reference
Burge,Tyler: 'Truth, Thought, Reason (on Frege)' [OUP 2001], p.363