It's used not only in special node editing (for Event Happens and If Event Happened?)
but also in the Townperson Advanced, Talk Node, and Quest editors.
A way to set this flag is not yet exposed in the scenario editor.
The flag is intended only for non-stackable items, but this currently isn't enforced.
Items now have a maximum number of charges, which is equal to their default number set in the item record.
Enchanted items with charges are now rechargeable.
