Hi there,
i just stumbled upon the missing "DAUB papers" assets as well - I bought the DAUB Watercolor & washes pack and used the new account download feature inside Affinity Photo 1.9x (which is unocked, once you registered).
So there are assets - if you watch just the first minute in the video of the spotlight article (linked above by Dan C) you see them installed in the assets panel ... and to be honest these Paper Stack assets are essential or an awesome feature - depends on the creative abilites & perspective 😉.
But thery are not installed correctly via the Affinity Photo "in app download feature" - the catogory inside the assest panel will be created, but its empty.
The solution : login into your shop account via the browser and download the *.afassets file titled "Papers" (around 470 MB) and the install it manually - using the assets panel settings dropdown and "Import Assets ..." menu option, which will create a secondary "DAUB Papers2" category ... and by some update magic also the original category "DAUB Papers" gets populated with the papers as well ... sounds like a bug.
cheers artify