postgres=# \dx
                                     List of installed extensions
        Name        | Version |   Schema   |                        Description                        
--------------------+---------+------------+-----------------------------------------------------------
 pg_stat_statements | 1.6     | public     | track execution statistics of all SQL statements executed
 plpgsql            | 1.0     | pg_catalog | PL/pgSQL procedural language
(2 rows)

postgres=#