[rt-users] How does RT find an existing ticket for a new email?

[Gary Oberbrunner]

Hi folks.  Quick question: I know RT can use the subject line [rt #XX] to find
an existing ticket for an incoming email, but if that's missing, e.g. because
the customer just emailed me about the ticket, can RT figure it out in other
ways, using email headers like References, In-Reply-To or Thread-Index?  Where
in the source would that be?

-- 
Gary