Nothing and Common Lisp includes second. But that's not caar. It returns the first element of the first element of a list - the extended forms of car and cdr are for nested lists and nested lists can be used to implement many different data structures [and are also the data structure containing Lisp programs].

The extended forms of car and cdr provide a form of expression which is not obvious based on the construction of common non-Lisp languages even those that have very flexible lists and dynamic typing.