I don't really know how these news breaks out before they officially announced but most of the times, users with technical knowledge are able to see the when the code implementation for the addition of new cryptos and then go off to start a rumor. I've seen this play a couple of times before even with Binance API too. So except you're a geeky users with a lot of free time on your hands, there's no sure fire way to know what's going to be listed next, or when. You can bank on some of those speculations but don't go all in until it's officially confirmed.