That may be related to all the "Young" teasing earlier.
But what it is, I don't know. There was this talk of a YJ/TTG crossover that was supposedly the TTG season finale (with YJ telling TTG how to be proper heroes). But the season's done, and nope, no YJ. Maybe it's next season? Who knows.
What we do know is that Earth-16 is coming back as part of Grant Morrison's Multiversity... except it's not our Earth-16, it's the Earth-16 of Chris Kent, that annoying whiner from Countdown: Arena.
On the TTG crossover (I'm admin at wiki), Horvath confirmed that The Team (I don't know if 2010 or 2016, but imagine if Robin was on both at the same time, lol) will chastise the heroes for being more serious. It's airing as part of Season 2 which is barely airing it's first half of the third episode in a 26 (52 segments) episode order.