pg_available_extensions
   The pg_available_extensions view lists the
   extensions that are available for installation.
   See also the
   pg_extension
   catalog, which shows the extensions currently installed.
  
Table 52.66. pg_available_extensions Columns
| Name | Type | Description | 
|---|---|---|
| name | name | Extension name | 
| default_version | text | Name of default version, or NULLif none is
       specified | 
| installed_version | text | Currently installed version of the extension,
       or NULLif not installed | 
| comment | text | Comment string from the extension's control file | 
   The pg_available_extensions view is read only.