What is the purpose of empty class in Kotlin?

Question

I was going through Kotlin reference document and then I saw this.

The class declaration consists of the class name, the class header (

Answer 1

It doesn't make much sense as a final result. However it can be useful in active development and at a design time as a placeholder of some sort, which may be expanded in the future. Such terse syntax allows you to quickly define such new types as needed. Something like:

class Person (
    val FirstName: String,
    val LastName: String,
    // TODO
    val Address: Address
)

class Address

I think main reason this is specifically mentioned in documentation is to demonstrate, that language syntax in general can be terse, not that it is specifically created for common usage.