But this is a library. It's not a drop-in 'sortable list' component (which I agree could, and should, have built-in keyboard accessibility). It's a general purpose toolkit for setting up drag interactions.

Asking if it 'implements' keyboard accessibility is like asking if a box of hardware tools implements wheelchair accessibility – it might be possible to build something wheelchair-accessible using the toolbox, but that's up to you.

I completely agree that there are lots of devs who won't consider accessibility when using this or other DnD libraries, and that's a shame, but it's not the place of a DnD library to magically create an alternative keyboard UI that somehow corresponds with whatever drag-and-drop UI you've built using the library. That just couldn't work. A human needs to think about it.