There are many nice changes here in recent years. Is there a document or page that outlines and explains the changes to the Developer portal that resulted in the excellent Document Archive no longer being maintained? https://developer.apple.com/library/archive/navigation/# Is there currently a reliable way to search for all of the newer sample code and documents within one list/view?

I was trying to locate a version of Big Sur to test against, but attempting to download a version from App Store fails now. I was searching the downloads section here, and things seem to be organized a bit differently from the last time I searched. Are there still links to download past OS versions? If so, can someone please point me to a link for Big Sur? I also tried to just download via Terminal, but methods that had worked in the past seem to not work currently. Any help is greatly appreciated.