The * operator is known as the Spread Operator in Kotlin.

From the Kotlin Reference:

When you call a vararg-function, you can pass arguments individually, for example asList(1, 2, 3). if you already have an array and want to pass its contents to the function, use the spread operator (prefix the array with *):

It can be applied to an Array before passing it into a function that accepts vararg.

For Example...

If you have a function that accepts a varied number of arguments...

fun sumOfNumbers(vararg numbers: Int): Int {
    return numbers.sum()
}

Use the spread operator to pass an array's elements as the arguments:

val numbers = intArrayOf(2, 3, 4)
val sum = sumOfNumbers(*numbers)
println(sum) // Prints '9'

Notes:

• The * operator is also the multiplication operator (of course).
• The operator can only be used when passing arguments to a function. The result of the operation cannot be stored since it yields no value (it is purely syntactic sugar).
• The operator may confuse some C/C++ programmers at first because it looks like a pointer is being de-referenced. It isn't; Kotlin has no notion of pointers.
• The operator can be used in-between other arguments when calling a vararg-function. This is demonstrated in the example here.
• The operator is similar to the apply function in various functional programming languages.

Spread operator in Python and Kotlin are really much different things. Python lets you pass any positional arguments using an array. Kotlin lets you only pass vararg arguments.

And the reason why only arrays are supported is because vararg is internally represented as just array. So * in Kotlin does not really unpack anything. Actually, it is the opposite. If you declare a function with vararg then passed arguments are packed into an array. By using * you can pass an array directly.