The document discusses the issue of file formats and accessibility of digital information over time. It provides examples where important data stored in obsolete file formats became inaccessible, such as data from the 1976 Viking Mars lander mission and images stored by the BBC. The UK National Archives also faces the risk of losing some of its 580 terabytes of data in obsolete formats that can no longer be read. Access to file formats is critical for long-term preservation and access to digital information and knowledge.