Journal of the Whills
Hi, I'm new here. I did a search, and the most lively discussion of the "Journal of the Whills" was in an Ep 3 thread that is now closed. I know nothing of an in-universe journal that may appear or be referenced in RotS (I have avoided most spoilers), but this is the answer to what the original "Journal of the Whills" is, from a book I have that has the classic trilogy scripts in them (and developmental stages of the scripts are also discussed). Strait from GL himself:
“Originally, I was trying to have the story be told by somebody else (an immortal being known as a Whill); there was somebody watching this whole story and recording it, somebody probably wiser than the mortal players in the actual events. I eventually dropped this idea, and the concepts behind the Whills turned into the Force. But the Whills became part of this massive amount of notes, quotes, background information that I used for the scripts; the stories were actually taken from the Journal of the Whills.”