Looks like the author is still active and looking for funding: https://github.com/TachibanaGeneralLaboratories/download-navi
But development seems to have stopped indeed. There is a fork, with new developers, that is actively being worked on: https://github.com/Davilarek/download-navi
Looks like the author is still active and looking for funding: https://github.com/TachibanaGeneralLaboratories/download-navi
But development seems to have stopped indeed. There is a fork, with new developers, that is actively being worked on: https://github.com/Davilarek/download-navi