Merriam-Webster's defines "Proven" as follows:
\ ˈprüv \
proved; proved or proven\ ˈprü-vən , British also ˈprō- \; proving\ ˈprü-viŋ \
Definition of prove
1A: to establish the existence, truth, or validity of (as by evidence or logic)
1B: to demonstrate as having a particular quality or worth
2A: to test the truth, validity, or genuineness of the exception
2B: to test the worth or quality of specifically: to compare against a standard
Masonry Cosmetics defines proven as: "Does it last?"
1: Does the Stain last the test of time?
2: Will the Stain hurt your brick? Will the Stain trap water? Will the stain cause your brick to spall?