Gents,
I talked to the builder last night. He said for strength there is rebar in it, plus there is fiber mesh. He said the approx depth is 5" by house and 4" at garage door. It is 40 grade concrete. He also said (like some of you) that the reason those cuts are there is to channel the crack which is due to shrinkage. He said in 10 years it should still look the same and if it is not separated or offset there is no reason for concern. He swears it is not going to be a problem.
I guess I will try to forget about it......and have a few beers this weekend....or maybe a 6 pack!