In Ruby who's already there in main?

When you open a Ruby file who's already there?

puts self.inspect # main
puts self.__id__ # 16 
puts self.class.name # Object

puts method(:inspect).owner.class # Object

Why does inspect say main? 

This is a special case defined in the Ruby implementation:

docs.ruby-lang.org is explicit about this behavior

What other objects were instantiated before the main one? It seems only another one: Class