NULL pg_database.datacl

Hi. I'm surprised, I thought ACLs would never be empty for a database.
Does that mean nobody can connect to this database?
I guess SUPERUSER and/or its datDBA can?
What does a NULL AclItem[] mean exactly?
(BTW, datallowconn is true)

Thanks, --DD

ddb=> select datname, datdba::regrole::text from pg_database where datacl
is null;
datname | datdba
---------+--------
qadb | qauser
(1 row)

PS: Was also surprised with #42883: ERROR: no binary output function
available for type aclitem
Thankfully datacl::text[] works fine in binary mode.