Frankly, the only plausible thing I was able to come up with would be a potential REBUTTAL WITNESS, since their identities don't, depending upon the state and the testimony they're expected to give, have to be disclosed in advance of the trial.
In LA, an attorney does not have to disclose rebuttal witnesses' identities, but you better be darn sure you know who does and doesn't qualify as a rebuttal witness before you take that gamble. I cringed while watching a judge rule that a particular witness did NOT get to testify and the attorney lost his case. (Appeals, malpractice alerts, anyone?!?!?)
Anyhow, so maybe JBaez thinks he's got a potential rebuttal witness and, since it's not a document, and maybe FL is like LA and - although he doesn't have to disclose his rebuttal witness's identity - he can't FIND the rebuttal witness, so maybe he needs a court order to help him locate the immediate whereabouts of the potential rebuttal witness.

eek: Casey has him looking for ZANNY!?!?!?

J/K...)