It would've been written by Man of Steel, Batman Begins, and Blade II writer David Goyer.
. “There was just a lot of behind [the scenes] stuff going on at Lucasfilm at the time,” Goyer said. “But it’s a cool script.”Soon after, del Toro himself confirmed the news on X. “True,” the director posted. “Can’t say much. Maybe two letters “J” and “BB” is that three letters?” Yes, Guillermo, it is. Three letters that are in the name Jabba in fact. But he, of course, didn’t say anything beyond that. Here’s del Toro’s confirmation as well as Goyer’s quote.
Goyer mentions two other things too. First, he says the del Toro drama happened about four years ago, which is telling. He also says he wrote a “script-ment for an Origins of the Jedi movie...that took place 25,000 years before the firstFirst, four years ago would put the development around the release ofr.