Yes, it's Special Administration Console.

Not sure, I'm quoting directly from the article.

The same question has been answered in the linked GitHub issue, though the comment was marked as off topic.

It's special administrative console, more in depth info what that actually is in the comment.

https://github.com/processhacker/processhacker/discussions/7...

The highlighted comment has been marked as off-topic and requires logging in to view, which I'm disinclined to do from mobile. Is there a summary elsewhere?

Here you go:

  DavidXanatos
  on 16 Aug
  
  Interesting driver,
  is the process termination feature of PH the only thing MSFT has a problem with?
  I mean if its the only thing they don't like, may be its worth moving that feature into a separate tool or a plugin with an own unsigned driver?
  Also changing the name would be an option, if than all the problems can be avoided.
  @dmex
  dmex
  on 16 Aug
  Maintainer
  
      the only thing MSFT has a problem with
  
  MS refused to discuss anything and have ignored every email so who knows what their problem is.
  
      if its the only thing they don't like
  
  It's not the only thing.... There are recent changes to APIs that block and limit features when the caller isn't taskmgr.exe.
  
  Either way this discussion is offtopic from the KPH updates.