I don't quite understand the scope in Kotlin Gradl...

# announcements

[NurBahnhof]

I don't quite understand the scope in Kotlin Gradle DSL. I understand that gradle build script implicitly import some stuffs. But for example in this code:
application{ mainClassName="SomeClass" }
where do the name mainClassName come from? I'm setting some attribute here. But where is the object? Shouldn't it be something like:
application.mainClassName="SomeClass"

[NurBahnhof]

I get it now. I didn't know what lambda can access the property of a lambda receiver without the quantifier this.