Spock Prime or at least information he gave. Another possibility would be a Starfleet vessel crossing over from the Prime universe/reality similar to how the USS Defiant seen in "The Tholian Web" crossed over to the Mirror Universe.
I don't expect this new movie to spend any time reminding people there was a prime universe. I'd be surprised to even hear a namedrop for Nimoy's Spock.
Why confuse new audiences?