4what to expect from it
The tooltip implies you can open it. You cannot. It is decoration and nothing else, so do not stack a pile of them expecting loot.
Each one picks its wrapping at random when placed, the way books do, and the colors match the hats the town NPCs put on during a party. Buy a handful at once if you are decorating: mixing the variants is the only way to get a gift pile that does not look copied and pasted. The Party Girl only stocks it while the event is live.