Postgresql ERROR: relation "pg_catalog" does not exist because pg_catalog is a schema

I couldn't find anything in the postgresql manual as how to view its
 content. SELECT does not seem to work.
       
 What's the exact command and error message?

netilla=#  \dn
        List of schemas
        Name        |  Owner
 --------------------+----------
 information_schema | postgres
 pg_catalog         | postgres
 pg_toast           | postgres
 public             | postgres
 (4 rows)

 netilla=# select * from pg_catalog;
 ERROR:  relation "pg_catalog" does not exist

     
   
That would be because pg_catalog is a schema; you can't select from it.
If you want to see what's in there, use \dS.