Readme for the 4.01 engine patch says:

Fixed a problem where the "Unique Name" Noun would only query a single
object class. Bug 670084.

Looking at the bug, it says:
Added an attribute test-all-objects to token-unique-name. If set to
true, then
object class is omitted from search, else the operation's object class
is used

So how is this exposed? Does designer/iMan plugins know to take
advantage of this?