10 Star Wars Details Only Explained Outside Of The Films
8. Who Was Snoke? - Rise Of Skywalker Novelization)
This was sort of explained in the movie itself, but the secret behind Snoke's identity was expanded upon in TROS' novelization. Personally, I never cared who or what Snoke was. I didn't mind the explanation we got but I never needed it. After all, screenwriting rule 101: if no one in the story cares to ask who or what something is, you are under no obligation to explain.
But explain they did, and the explanation is that - due to circumstances Palpatine was in that we'll get into in a bit - Snoke was the lone successful result of a TON of cloning in order to make an agent that could actually go out and act out his orders in his stead. Considering how Snoke looked in films 7 and 8, one has to call into question Palpatine's definition of a success.
But of course, there were plenty of other attempts to make a clone of Palpatine before they landed on Snoke as the success. Which is how we got our next entry.