There was nothing unusual about that script. That's how you do it. There was a "script guru" back in the early '00s who made the argument that every single first draft that had ever been written could improve simply by ditching the first 30 pages.

Beginning writers have this urgent need to explain all the cool shit they've thought of and hang up all the bangles and shine all the sparkles and backstory the ever loving fuck out of the poor dumb bastard making $15 to read this thing and write 1000 words on why it sucks and they don't realize that THE AUDIENCE OWES YOU FUCKALL. Then you get into novels and shit is even more brutal: The rule William Goldman, Blake Snyder and Syd Field all used is "you have ten pages to hook your audience." The rule Sol Stein uses is "they're going to pick your book off the shelf, open it, start reading the first page and if you don't have them hooked by the time they flip to page two you lose."

Star Wars - the whole fucking thing - is "He fought with your father in the Clone Wars."

Someone once wrote JRR Tolkien to ask what lay beyond the mountains of Mordor. He wrote her back to say "madam, if I told you, you would simply ask 'well what lays beyond that?' What is important is that I know what lies beyond the mountains of Mordor, not that you do."

There's a five page document that goes with that script. It lays out the next nine movies. It was created at the request of a collaborator. I fuckin' well know that world but nobody else needs to until there's a story happening in it.