This computer document is actually the historical information that was recorded over the years by Mildred Wyeth, a woman who found herself in the Deathlands and part of Ryan Cawdor's group of survivalists when she was brought out of cryonic suspension in Michigan.
The document was created after Mildred found a working computer and eventually fell into the hands of Lakesh, who distributed it throughout the Barony Archives like a virus. Brigid Baptist was one of the Archivists that the codex had been sent to.
It covered all the sites and places that Ryan's band of warrior survivalists had been to, as well as the mutated life-forms, the people, the environment, and relationships between the band members and others they came across.
More significant was her speculation into the truth behind the totality concept and its various branches. Due to the huge number of redoubts the group had jumped to, they discovered quite a lot of information. At one point she had entered data on the Archons as well.
Despite her high education, only the tip of the iceberg had been touched. The truth behind the concept and its various branches and divisions was still hidden away, only to be discovered by Kane and his fellow exiles.