Apparently it's there either because of God or the Devil.
There are more details in their paper from sept. 2014For Planck stars, if they (Rovelli & al.) can determine some unique enough signature of Planck star signals (didn't see that in the slides[,....])
We estimate the size of a primordial black hole exploding today via a white hole transition, and the power in the resulting explosion, using a simple model. We point out that Fast Radio Bursts, strong signals with millisecond duration, probably extragalactic and having unknown source, have wavelength not far from the expected size of the exploding hole. We also discuss the possible higher energy components of the signal.