I read elsewhere that it's basically built on what they are now calling their Lightship platform - the network of sites and data drops that they built for Ingress, then developed on to Pokemon Go and soon Harry Potter.
I think it will be interesting to hear the reviews of what the Harry Potter game is like and how distinct it is from Pokemon Go in order to assess what the TF game might be like.
I initially found Pokemon Go to be fun, but it became a bit of a time drain and increasingly got built for people who were much more advanced in the game and gave up.