Pretty soon there will be PA mountain lions made out of more than just stone.
So: "reestablished" means once there is good mountain lion documentation of two separate animals in Pennsylvania. Physical specimen for DNA evidence is best, but video is fine too as long as there's some way to be sure there are two different animals. Of course if it happens twice in a surrounding state it's just a matter of time, and PA is prime mountain lion country, so probably not much time at that. There's already one in Indiana.
So, even with my definition of "reestablished", would anyone bet against this? On one hand I like that a wilderness animal is returning to my home state's ecosystem; on the other hand I kind of like going for a run in the PA woods because I know nothing is going to jump out at me, unlike in CA.