Well, the size leads me to believe it may be a stripped down version of the SDK... though we all did fine with a stripped down 3.41 SDK for a LONG LONG time. ;-)
And before anyone asks... (assuming they haven't already)... NO, this won't lead to 4.00 cfw or keys.
If you are looking for >3.55 CFW (I.E. 3.66CFW) click here!
Want 3.70 Keys... TehRuler has them!!