The PlayerSmelted Event is fired whenever a player takes something out of a furnace.

You will need to cast the event in the function header as this class:
crafttweaker.event.PlayerSmeltedEvent
You can, of course, also import the class before and use that name then.

Event interface extensions

Link to event-interface-extensions

PlayerSmelted Events implement the following interfaces and are able to call all of their methods/getters/setters as well:

The following information can be retrieved from the event:

ZenGetterReturn Type
ZenGetter
player
Return Type
IPlayer
ZenGetter
output
Return Type
IItemStack