From Ammoland:

The case, Vanderstok v. Garland, was brought by the Firearms Policy Coalition (FPC) and challenged the ATF’s decision to reclassify unfinished frames and receivers as firearms. Biden and other anti-gun zealots have railed against Americans building their own guns in the privacy of their own homes. The anti-gun side of the debate has propagandized these items as tools of criminals and has labeled the items as “ghost guns.”