MISSING HEADERS ( * = difficult, - = quick, + = placeholder, x = won't do )
---
> NSATSTypesetter.h +
> NSCollectionViewCompositionalLayout.h *
> NSCollectionViewFlowLayout.h *
> NSCollectionViewGridLayout.h *
> NSCollectionViewLayout.h *
> NSCollectionViewTransitionLayout.h *
> NSDictionaryController.h -
> NSDiffableDataSource.h *
> NSDraggingItem.h -
> NSDraggingSession.h -
> NSFilePromiseProvider.h -
> NSFilePromiseReceiver.h -
> NSGlyphInfo.h -
> NSItemProvider.h + 
> NSMenuToolbarItem.h -
> NSOpenGLLayer.h +
> NSTableCellView.h *
> NSTableRowView.h *
> NSTableViewRowAction.h *
> NSTypesetter.h +
> NSUserActivity.h -
> NSWindowTab.h +
> NSWindowTabGroup.h +
