Question mark in place of attribute name?

[Michael.Smith@domino1.cuny.edu]

This is a stupid newbie question, I'm sure, and this 
probably isn't the place to ask it either, but my openLDAP 
server is getting search requests from a Websphere instance 
that look like this (this is the log entry, not the line trace): 

SRCH base="uid=foo,ou=people,dc=bar,dc=com" 
        scope=0
        deref=3
        filter="(|(objectClass=*)(?=undefined))" 

What's with this "?=undefined" thing? Is this a legit 
search syntax? What does it mean? 

Thanks in advance for all the light I'm sure will be shed -- 

--Michael Smith
--ms@gf.org