And to make them actually show up as trading vessels in your game, you need to edit career.rules and look for //Fringe under TradeShips, and add these ships:
(careful: the labels, eg. fringe_3a, have to be unique per ship. These new ships have unique labels, otherwise the game won't start.)
// Fringe
fringe_1a : ~/BaseTradeShip { ShipID="Veloci"; Faction=fringe; TierRange=[1, 7]; StasisSpeed=87; StasisTradeTime=30; }
fringe_1b : ~/BaseTradeShip { ShipID="Pawn Prawn"; Faction=fringe; TierRange=[1, 7]; StasisSpeed=87; StasisTradeTime=30; }
fringe_3e : ~/BaseTradeShip { ShipID="Stirner"; Faction=fringe; TierRange=[1, 8]; StasisSpeed=50; StasisTradeTime=40; }
fringe_3f : ~/BaseTradeShip { ShipID="Cospito"; Faction=fringe; TierRange=[1, 8]; StasisSpeed=50; StasisTradeTime=40; }
fringe_3g : ~/BaseTradeShip { ShipID="Hoodlouse"; Faction=fringe; TierRange=[1, 9]; StasisSpeed=69; StasisTradeTime=40; }
fringe_3h : ~/BaseTradeShip { ShipID="Combus"; Faction=fringe; TierRange=[1, 9]; StasisSpeed=69; StasisTradeTime=40; }
fringe_3i : ~/BaseTradeShip { ShipID="Mule"; Faction=fringe; TierRange=[1, 9]; StasisSpeed=77; StasisTradeTime=40; }
fringe_3j : ~/BaseTradeShip { ShipID="Extended Warranty"; Faction=fringe; TierRange=[1, 9]; StasisSpeed=77; StasisTradeTime=40; }
Finally, you need to restart your game and the ships will start showing up in Fringe systems.