[c-nsp] What is the fpd package used for in newer IOS releases?

[John Neiberger]

I've done some recent upgrades from 12.2(18) up to 12.2(33) and we've
been having to put an fdp package on flash along with the actual IOS.
I've yet to find out exactly what those are for. I was told by another
more senior engineer that they need to be there, but that's the extent
of my knowledge of them. Can any of you shed some light on these
mysterious packages?