Probably their Data Provenance, which tracks everything that happened to the data.<p><a href="https:&#x2F;&#x2F;cwiki.apache.org&#x2F;confluence&#x2F;display&#x2F;NIFI&#x2F;Persistent+Provenance+Repository+Design" rel="nofollow">https:&#x2F;&#x2F;cwiki.apache.org&#x2F;confluence&#x2F;display&#x2F;NIFI&#x2F;Persistent+...</a>