The accompanying publication explains it more: <a href="http:&#x2F;&#x2F;www.dmst.aueb.gr&#x2F;dds&#x2F;pubs&#x2F;conf&#x2F;2015-MSR-Unix-History&#x2F;html&#x2F;Spi15c.pdf" rel="nofollow">http:&#x2F;&#x2F;www.dmst.aueb.gr&#x2F;dds&#x2F;pubs&#x2F;conf&#x2F;2015-MSR-Unix-History&#x2F;...</a><p>&gt;Curating  and  processing  available  snapshots  as  well  as old and modern configuration management repositories allows the  reconstruction  of  a  new  synthetic  Git repository  that combines under a single roof most of the available data