Description
Causes your attacks to ignore 3/6/9% of your target's Armor and increases the damage dealt by your Rupture ability by 10/20/30%.
Position confidence
row: Confirmed (talentsforever.com JSON + foreverchanges.pro tier listing); column & arrow: Reported (explicit only in talentsforever.com data/rogue.json)
Change notes
Classic armor penetration was a flat amount that scaled with level.