The pg_available_extension_versions view lists the specific extension versions that are available for installation. See also the

The view pg_user_mappings provides access to information about user mappings. This is essentially a publicly readable view of

The catalog pg_proc stores information about functions (or procedures). See

The pg_enum catalog contains entries showing the values and labels for each enum type. The internal representation of a given enum value is

The view pg_policies provides access to useful information about each row-level security policy in the database.

The catalog pg_conversion describes encoding conversion procedures. See

The view pg_shadow exists for backwards compatibility: it emulates a catalog that existed in PostgreSQL before

The catalog pg_default_acl stores initial privileges to be assigned to newly created objects.

The catalog pg_largeobject_metadata holds metadata associated with large objects. The actual large object data is stored in

The catalog pg_cast stores data type conversion paths, both built-in and user-defined. It should be noted that