I can't imagine the insurance file being little more than the full uncensored cable archive. What else could it be? If Wikileaks had a gigabyte of compromising information on the US government or some other powerful entity, surely they would release it? Isn't that their stated mission?
From what I gather it sounds like they're trying to redact important info from cables prior to release so they don't get their asses burned any more than they have. They've got a collection of cables they haven't yet processed and are now being leaked.
Wikileaks has demonstrated a propensity to keep things close to chest. Perhaps the insurance file contains private documents not yet released that are personally embarrassing to important individuals (e.g., those likely to be involved in the extradition and/or untimely demise of Assange) but not particularly relevant from a national standpoint. Not sure, but I definitely don't think that the cables are the only potential information contained in the insurance file. Wikileaks, especially after their bout of airtime last winter, got a lot of data from a lot of different sources. There's a lot of stuff there to collate.
