pg_description   The catalog pg_description stores optional descriptions
   (comments) for each database object.  Descriptions can be manipulated
   with the COMMENT command and viewed with
   psql's \d commands.
   Descriptions of many built-in system objects are provided in the initial
   contents of pg_description.
  
   See also pg_shdescription,
   which performs a similar function for descriptions involving objects that
   are shared across a database cluster.
  
Table 51.19. pg_description Columns
| Name | Type | References | Description | 
|---|---|---|---|
| objoid | oid | any OID column | The OID of the object this description pertains to | 
| classoid | oid |  | The OID of the system catalog this object appears in | 
| objsubid | int4 | For a comment on a table column, this is the column number (the objoidandclassoidrefer to
       the table itself).  For all other object types, this column is
       zero. | |
| description | text | Arbitrary text that serves as the description of this object |