SingletonList/SingletonMap - common Kotlin

Just out of curiosity:

Java does provide a listOf()/mapOf() with 1 argument to create the SingletonList/SingletonMap.
Is there a specific reason why common-Kotlin doesn’t provide this optimization?
Or is this just an oversight/skippd for the moment to safe some time?

Are you talking about method below (link to docs)?

fun <T> listOf(element: T): List<T>

Singleton List is created here…