Under the hood, Kotlin is actually calling the component function

desctructureUnderHood.kt

//example
data class Items(val one: String, val two: String)

val items= Items("1","2")
val (one, two) = items 

//converts to 
val one = items.component1
val one = items.component2

// means a getter function/operator/field is already present in those 
// class which automatically popluates these fields

// What the creators of Kotlin did was actually implement 
// 5 extension functions on many of the classes in the
// Collections.kt library that we commonly use.

operator fun <T> List<T>.component1(): T
operator fun <T> List<T>.component2(): T
operator fun <T> List<T>.component3(): T
operator fun <T> List<T>.component4(): T
operator fun <T> List<T>.component5(): T