AFAIK, on the Mac the sort order is simply left to right and sequential the way people would sort, ie 8, 9, 10, 11 when it comes to numbers.
Windows used to sort numbers differently, they put 10 and 11 ahead of 8 and 9 since the teated the "10" as a 1 and a 0
Don't know if that is still true, it's certainly still that on Acrobat 9 that I use.
There must be an Apple document somewhere that specifies the sort order when it comes to letters vs numbers bs special characters etc.
From what I see with a little bit of testing is that numbers are sorted ahead of letters, a space is sorted ahead of either one, capital and lower case letters are treated the same in sorting.
Pretty much the same way I would sort manually