pg_foreign_table
   The catalog pg_foreign_table contains
   auxiliary information about foreign tables.  A foreign table is
   primarily represented by a pg_class entry,
   just like a regular table.  Its pg_foreign_table
   entry contains the information that is pertinent only to foreign tables
   and not any other kind of relation.
  
Table 51.25. pg_foreign_table Columns
| Name | Type | References | Description | 
|---|---|---|---|
ftrelid | oid |  | OID of the pg_class entry for this foreign table | 
ftserver | oid |  | OID of the foreign server for this foreign table | 
ftoptions | text[] | Foreign table options, as “keyword=value” strings |