This is impressive, although perhaps not too practical. They are using lines scribed on tungsten. The underlying data is expressed as QR codes (which will be forgotten in a few centuries at most, but that is a different problem.)
One problem is that they are using 100nm line width. While impressive, at that width it is invisible to optical devices (which have a limit of approximately 1 micron) without very complex optics and electronics. So they are going for high density, rather than long-term readability. On the other hand, it would be great for a 50 to 100 -year storage, which is longer than any existing technology can reliably handle.