Proof Terms ???

Just been reading a report on ranking factors in 2014 and come across 'Proof Terms' ???
Any idea what this is?

The PROOF terms are an agreement to the PROOF service. PROOF meaning Protected Online Filing, this refers to a scheme that allows companies to protect themselves from online fraudulent filings, but for more information we suggest that you take a look here: http://www.companieshouse.gov.uk/infoAndGuide/proof.shtml