Think libraries in the old days before we had computers.
Index cards filed by subject, name, etc. = card file
Yep. Scans of card files. The first one says that Anderson, Sturgis, Buckley and Hunt (top)
are connected to Watergate and Buckley.
More info is available in IG file #13
This card is from Watergate in 1975 but in the body they're asking the FBI-CIA for Howard Hunt's vacation and leave records during JFK's assassination period.
That's weird