Specifically it was being made by Epic back when Fortnite was a PvE tower defense game. Once they started to dabble in the BR genre, they redirected all available resources to the money printer. Can't say I blame them, but I was really looking forwards to the potential of an open source UT game. Modding scene was gonna be lit.
They're making so much money with Fortnite they could pick up this project again silently and release a finished product to the fans that were let down.