This field will create a textual representation of the object. This is needed e.g. to be able to generate a path. You can in this field combine normal text and reference to attribute identifiers. E.g.
"User <first_name>, <last_name>" Would generate a string which always startes with User followed by the first name and last name for that given user. The values inside <> must be a valid identifier. eZ publish will default to the first identifier.