Find current owner of custom data type?
Up until 9.4

You can go and ask the system catalogs (pg_type, to be precise):

SELECT rolname 
  FROM pg_type t 
  JOIN pg_authid r ON typowner = r.oid 
 WHERE typname = 'bla';

 usename 
─────────
 dezso


From PostgreSQL 9.5 on

From this version on, there is a new object identifier type called regrole, and it makes the query a bit simpler:

SELECT typowner::regrole 
  FROM pg_type t 
 WHERE typname = 'bla';


But there is more to it - the new 9.5 version of psql already displays the owner when using \dT+:

      Schema       | Name | Internal name | Size | Elements |  Owner   | ...
-------------------+------+---------------+------+----------+----------+ ...
 zel_api_r14_00_09 | bla  | bla           | 4    | a        | postgres | ...