J-31 is not a UCAV, if anything LingLong would be the J-31. From the design we've seen so far, it has high potential for naval aviation, and would be China's 2nd generation naval fighter, J-15 being the 1st gen.
He translated it wrong. It says "Export medium stealth fighter", not UCAV, and anyone else who can read Chinese will tell you the same. Project 310 is "J-31".