SELECT * FROM pg extension;

SELECT * FROM pg_extension;

 extname | extowner | extnamespace | extrelocatable | extversion | extconfig | extcondition
---------+----------+--------------+----------------+------------+-----------+--------------
 plpgsql |       10 |           11 | f              | 1.0        |           |
(1 row)

See also

• PostgreSQL, PostgreSQL extensions, CREATE EXTENSION, List extensions (\dx)