First off, you guys are awesome for putting this stuff together.  Can't thank you enough.  Haven't actually done anything with it yet, just reading and researching as much as I can before I get into it.

In my researching I did find a post where it says that for the graphics A, B, and C designations they mean:

A = Active
B = Business
C = Catchall.

I found that incredibly helpful.  I would like to know if there's some kind of similar rationale for the sound A and B.

If a little post with that information (for all packs that have A, B, C..) could be created and stickied in the FAQ section that would be awesome!

Thanks so much!