Opening the e-file in King's Indian Defense? I'm reading about KID in "The Complete Book of Chess Strategy" by Jeremy Silman, and I don't understand one of his points. He gives the following moves (which is the "Averbackh Variation"):

1.d4 Nf6
2.c4 g6
3.Nc3 Bg7
4.e4 d6
5.Be2 0-0
6.Bg5 c5
7.d5 Qa5
8.Bd2 e6

Which he says (of Black's plan) "...opening the e-file for his Rooks". But I don't see that. There's no way white would go 9.exd6 when 9.exf6 is there, unless we are talking a Knight sacrifice with 9.exf6 exf6. But even then, the e-file is not totally open with a Bishop at e2. 

So I guess my question is if I'm reading that right, or if there is maybe some typo/error here. Black sacrifices his Knight for a partially open e-file?
I am not sure if you are leaving something out, but what he means is that depending on what white does, assuming it does not lose, black may play e6xd5 and then Re8 to get play either against e4 if white recaptures with c4xd5, or possibly other play down the open file should white respond to e6xd5 with e4xd5.

I also think you may be misreading the notation since there is not going to be exd6 or exf6.