Yep, all the differences are being discussed over in the General subforum.
General consensus seems to be that the Disney+ versions are the 2012 Reliance 4K scans that Lucas was preparing for the 3D releases that got scrapped, and according to Pablo Hidalgo, that Greedo scene change was the last alteration George made to the film(s) before he sold LFL to Disney.
So, it would’ve been one last change that would be introduced in the cancelled 3D release, despite not being in the 2011 Blu-ray?
Yep. I personally would speculate that Lucas was initially attempting to update the 2004 master for 3D and found it lacking when converted (maybe he finally noticed the horrid color work), so he just dumped what they’d already finished on the BR release and then had new 4K scans done with the intention of using those for the 3D release, all changes he’d already made that ended up on the 2011 release included. And then he just couldn’t resist one last tweak on top of that…
But then 3D re-releases turned out to not be terribly successful and he sold the company, so his new 2012 masters were shelved.