The fruit's tough peel hides a corrosive latex layer that can blister skin and lips raw, meaning it has to be handled carefully long before it ever becomes a pickle.
The flesh and grated seed of the wild bambangan mango, a fruit found only in Borneo's forests, are salted and left to ferment into a pungent, sour-savory condiment. Sabah markets sell it in jars alongside other native pickles, and it's often stirred into hinava for extra tang.