https://thehill.com/regulation/court-battles/4304682-appeals-court-atf-ghost-gun-rule/ saying that this much lampooned federal agency exceeded its statutory authority. I believe this was a unanimous decision.
The disturbing thing is that, if the current law is interpreted literally, then it delegates the legal decision-making power from Congress to the head of federal agency -- some unelected bureaucrat -- to decide what guns and gun parts are illegal. That's the problem with laws that give the force of law to regulations, part of a bigger legal issue that's definitely not specific to just the issue of guns. Of course there are provisions written into the Constitution, but we all know how those can be so often and easily ignored.
related older thread about this issue: Democrat's latest clever strategy at gun control (posted in "Gun Control" section, Apr 12, 2022)
I looked to see if there was an active thread and If I had seen one in my cursory review, I would have posted that decision on it.
