`IsItemBound`

ESO Lua API function — used by 37 of the 3,030 addons we indexed (combined 4,619,220 downloads). Signature from the official ESOUIDocumentation.txt, API version 101050.

Official signature

IsItemBound([Bag|#Bag] bagId, integer slotIndex)

Returns: bool isBound

Real usage — from Advanced Filters - Updated (Inventory sub- & dropdown plugin filters)

                    if isGuildBankDepositPanel or isGuildStoreSellPanel or isMailSendPanel then
                        isBound         = IsItemBound(bagId, slotIndex)
                        isBOPTradeable  = IsItemBoPAndTradeable(bagId, s

Short excerpt from the shipping addon Advanced Filters - Updated (Inventory sub- & dropdown plugin filters) — its ESOUI page; the code belongs to its author. Shown because documentation without a working example is half a reference.

Most-downloaded addons using it

Addon	Total downloads
Advanced Filters - Updated (Inventory sub- & dropdown plugin filters)	2,602,223
Dustman	1,178,205
Set Collection Marker (Sticker Book)	135,099
Bandits Loot Manager	134,811
Craft Bag Extended	123,395
Mass Deconstructor	112,328