51.66. 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 51.67. 
    
     pg_available_extensions
    
    Columns
   
  
| Name | Type | Description | 
|---|---|---|
| 
        name
        | 
        name
        | Extension name | 
| 
        default_version
        | 
        text
        | Name of default version, or 
        NULL
       if none is
       specified | 
| 
        installed_version
        | 
        text
        | Currently installed version of the extension,
       or 
        NULL
       if not installed | 
| 
        comment
        | 
        text
        | Comment string from the extension's control file | 
  The
  
   pg_available_extensions
  
  view is read only.