Reinforced Cache Key

Reinforced Cache Keys have a chance to drop from the following Zanj'ir naga in Nazjatar:
 * Zanj'ir Brawler
 * Zanj'ir Centurion
 * Zanj'ir Myrmidon
 * Zanj'ir Scaleguard
 * Zanj'ir Stalker
 * Zanj'ir Trapper

Objective of

 * Reinforced Cache (quest)