TU Dresden Article about it. https://tu-dresden.de/ing/informatik/sya/ps/chair/news/geheime-daten-auf-dem-druckpapier-diplominformatiker-der-tu-dresden-entwickeln-verfahren-gegen-druckerueberwachung

It has a link to the App that decodes, what being embedded in the print and anonymize the prints, by scrambling the yellow dot patterns. https://dfd.inf.tu-dresden.de/

You just need to spend a few hours trying weirder and unique ways to frame the issue and you might find the answer.