As far as I can tell, lbData returns the class names of inventory items (e.g. ToolKit), which is really neat. Unfortunately lbData returns an empty string for backpacks in containers.

Having backpacks returned via lbData would allow https://github.com/CBATeam/CBA_A3/pull/1329 and ACE' inventory filtering (https://github.com/acemod/ACE3/blob/74de646a0237d558655e6c4b227791c466c4dc43/addons/inventory/functions/fnc_forceItemListUpdate.sqf#L34-L41) to work better.