The DR-DOS/OpenDOS Enhancement Project

exFAT is proprietary, just like NTFS. Given their track record, M$ will never freely publish the specs (see the link).

With M$ pushing it, and hardware vendors buying into it (which they always will -- this is M$, after all) exFAT will need to be supported if you want DOS to work with newer hardware. It is a very bad idea to simply ignore exFAT and hope it goes away or that you will never need to deal with it. It really doesn't matter if FAT+ or some other option is "better" or more compatible.

Also, M$ is specifically directing exFAT at portable storage devices (like those that attach through USB ports), since other options (like NTFS) have way too much unnecessary overhead. M$ itself recommends that you NOT use NTFS on portable devices.

I can see a day coming in the not too distant future when nearly all USB flash drives, cameras, etc. will come formatted natively in exFAT. I can also see a day coming when M$ will not support FAT32, or maybe even FAT16 or FAT12, at all. They've already done things like stopping support of multiple partitions on portable media.