Real World article
(written from a Production point of view)

A-13 was a spatial location in the Milky Way Galaxy.

During the Whale Probe crisis of 2286, a Starfleet Command Table Operator reported the probe had passed by this location. At the time of the passing, there was no new data available on the probe. The line mentioning this location was cut from Star Trek IV: The Voyage Home. [1]