I don’t believe there’s a thread on this forum about it, but instead it’s over at TheStarWarsTrilogy forums, where the 4KXX series and the Silver Screen Edition scans originate from.

Short version - it’s essentially a “de-specialized edition” that uses the Disney+ files as the base, and replaces shots as necessary from the 4K77 and 4K80 scans to make the 2012 Lowry re-masters as close to theatrical as possible. It’s not as involved as Harmy’s Despecialized projects, which involved a lot of blending and matte-work, it seems to mostly just be replacing whole shots when a change comes up. It’s notable that the 4K80 project isn’t very close to completion yet, but the scans themselves have been made available to Oohteedee for use in his project.