There are already interfaces for Immutable collections in kotlin. And all the functional operators as map, filter, etc, returns them. But it is not true immutab

There are already interfaces for Immutable collections in kotlin. And all the functional operators as map, filter, etc, returns them. But it is not true immutability as you said, because under the hood they are normal list. They aren't even read-only objects, but you encapsulate this behaviour under an interface.