Provide a detailed and clear description of feature or change that you want to offer.
Ideally we should do a mixin into slotsChanged of EnchantmentMenu and derive information on what player does container belong to by going over container slots.

Describe why you want this. If there's a reason.
Back in the day this functionality was achieved by using EnchantmentLevelSetEvent, but this event provides us with no context regarding what player is enchanting level actually set for. As a result, the way it works currently is scanning 16x16x16 area centered on enchanting table for players, and increasing enchanting level if cursed player is found. Understandably, this is not a perfect solution.