Good thread. It takes a fair bit of time to put up a post like that.
The debris, as far as I know, is excess crankcase sealant which has found it's way up through the impulse line. Stihl are well aware of this problem.
As regards finding details on exact models of carbs Zama have a excellent website: http://www.zamacarb.com/tips.html
Just go there and enter the model no of the carb in the "Product Look Up" link to get the full IPL or download the Quick kit Cross Reference