6.2.3 Preservation Metadata The metadata needed to manage preservation processes at the ingest stage is all the information regarding the creation of the digital audio object and the changes to format that have occurred prior to ingest. In this way the technical provenance of the object is preserved, which allows a pathway between the present form of the item and original from which it was created to be traced. BWF has a non-compulsory recommendation for BWF entitled “Format for CodingHistory field in Broadcast Wave Format” http://www.ebu.ch/CMSimages/en/tec_text_r98-1999_tcm6-4709.pdf which describes how changes to the file may be described. Local usage of the ASCII free text field allows the description of the technical equipment or software that was used in the creation of the digital audio object.