This is SPIS. SPIS originally stood for SPlit Item Stacks, but now it's just four letters. The purpose of SPIS is to add durability to weapons and armor in Skyrim. This is achieved through adding custom BSExtraData to all the weapons and armor the player comes in contact with, and then saving them and restoring them through devious means. CBED is a group of helper functions to do some of the heavy lifting of implementing custom BSExtraData types.