Can't remove default permissions entry

On RDS (thus, no superuser) we are trying to drop a user. The only remaining item that the user owns is an "empty" default permissions entry, but we can't seem to get rid of it so that the user can be dropped:

I'm sure I'm missing something obvious!

Logged in as xyuser:

db=> \ddp+
Default access privileges
Owner | Schema | Type | Access privileges
------------+---------------+----------+--------------------------
xyuser | | table |

db=> ALTER DEFAULT PRIVILEGES FOR USER xyuser REVOKE ALL ON TABLES FROM xyuser;
ALTER DEFAULT PRIVILEGES
db=> \ddp+
Default access privileges
Owner | Schema | Type | Access privileges
------------+---------------+----------+--------------------------
xyuser | | table |

db=>

--
-- Christophe Pettus
xof(at)thebuild(dot)com