The arrival roster at Deep Space 9 listing the G'Mat
The USS G'Mat was a Federation starship that was in service with Starfleet in the late 24th century. In 2370, under the command of Captain W. Bligh, this ship departed from the System C-111 bound for Deep Space 9, and was scheduled to arrive at the space station on stardate 47560.5. (DS9: "Whispers")
The G'Mat was never mentioned or shown, it was simply listed in an okudagram graphic of an arrival roster on a viewscreen. No reason for the ship's odd nomenclature has been noted, but the graphic was also populated by some other in-jokes.