Please describe the new feature or change.
It would be nice if there will be a possibility to render an overlay when wearing an item in a curio slot. Like the overlay when wearing a carved pumpkin on head. In Forge there is already a possibility to add it for items wearing in vanilla armor slots but I cannot find a way to do it for curio slots.

Please describe why you want this feature.
My mod (Useful Hats) adds an aquanaut helmet to the game and when on head it renders an overlay (see here). Recently I added the support for Curios and I found out that there is no possibility for me to render it when in curios head slot.

This is a hella specific feature if you'd ask me. But I can try to figure this one out and make a pull request to forge branch on the matter if @TheIllusiveC4 confirms that it totally makes sense in an API.

That would be very nice! :)

Hmm, it is rather specific. It might be a little too niche. Also, can't you subscribe to the RenderGameOverlayEvent (or whatever it's called), listen for the helmet overlay, and render your logic in that? Basically, wherever Forge does their logic for their IForgeItem#renderHelmetOverlay method.

Okay, I will try to use the RenderGameOverlayEvent. Thanks for the hint! :)