PostgreSQL - Who or what is the "PUBLIC" role? I was looking at information_schema.role_table_grants when I saw public in grantee column, then I've checked at information_schema.enabled_roles but this role_name does not exist.

=> Who or what is the public role?
Right from the manual: 


  The key word PUBLIC indicates that the privileges are to be granted to all roles, including those that might be created later. PUBLIC can be thought of as an implicitly defined group that always includes all roles. Any particular role will have the sum of privileges granted directly to it, privileges granted to any role it is presently a member of, and privileges granted to PUBLIC.