The bronze broken vane part is a quest item used in One Small Favour. It's obtained by climbing onto the roof of Phantuwti Fanstuwi Farsight's house in Seers' Village and examining the weather vane there.
The ornament needs to be repaired with a bronze bar, which turns it into an ornament. If you lose the broken vane part, Phantuwti will charge you 330 coins. Once repaired, the parts can be returned to their position on top of the house in order to continue with the quest.
The update history project is a work-in-progress – not all updates to this topic may be covered below. See here for how to help out!