Minecraft 1.16.4

As per this old request: #3162

But for CuriosAPI instead of Baubles.

I've tried assigning it the the 'back' curio slot with a datapack, but functionality (and equipped player model) is not maintained.

Meh, low priority.
If Curios is Capability, I'll consider it, otherwise it's a hard no.

It uses tags to specify which slots an item is placeable in, and has a capability yes.