These 2 indicate 32 and 64bit architectures, and are the only choices. I could switch those 2 with 'any', but it would mean the same thing.

See - https://wiki.archlinux.org/index.php/PKGBUILD#arch

And  - http://superuser.com/questions/238112/what-is-the-difference-between-i686-and-x86-64