Indeed, all \d* which display perms have the empty/default confusion: \dp \ddp \des \dew \l \dn \db \df \dT \dD \dL I fixed them all to display the default acl in the patch I just sent. I also noticed that although large objects have permissions, they are not printed by any backslash commands.
I tried your patch. From my point of view this is desirable behavior. Hopes this patch will be included in v12.