If your a pilot you know that you always have certain Documents that you take on each flight IE; maps, checklists, itinerarys ect. This is basically a way to eliminate clutter in the cockpit and create and easier way to access the information needed for that flight. Its like having a kneeboard(EFF) in your flight bag (EFB).
What is electronic Flight Folder (eFF)? Why are airlines interested?
Why is it important for airlines to study its XML Schema?
eFF is a data structure for an Electronic Flight Bag (EFB)-hosted
application, that allows the pilot to read and manipulate briefing
information electronically. eFF content could also be used by applications
The use of an „electronic Flight Folder“ application allows the airline to
eliminate physical paper transports to and from the aircraft
In combination with the availability of in-flight IP connections, briefing
information could be updated in-flight, e.g. by new satellite pictures
XML describes the content of a document, e.g. a briefing package, The
eFF and FlightPlan XML Schemas define how data contained in the
briefing package can be interpreted by airborne applications
--courtesy of Lufthansa
and check this out-> http://www.arinc.com/aeec/projects/aoc/what_is_eff_v1.pdf