How to find Intel SKU for Mac CPUs

Seems like everywhere you can go to purchase a laptop they specify the Intel SKU for each CPU option - except Apple. If you have a Mac, you can apparently find this info using the following command:

sysctl -n machdep.cpu.brand_string

For instance, on my Mac, this returns:

Intel(R) Core(TM) i5-3330S CPU @ 2.70GHz

The number I am interested in here is the "i5-3330S", the Intel SKU.

However, if I don't own a Mac, how can I find this info? It doesn't seem to be anywhere on Apple's web site, even in the tech specs. For instance, Apple just announced a new 2015 MacBook, and a refresh to the 13" MacBook Pro lines. Where/how can I find what CPUs are actually in these products?

Update: It appears that Wikipedia now lists the Intel SKUs for the latest (2015) Macs. For instance, from the MacBook Air page it shows the latest Air (sic) model uses an i5-5250U with an optional i7-5650U. However, footnote 55 cites a Apple's own specs page which not only contain no SKUs as far as I can see, but aren't even for the new 12" model! So where is this info coming from?