Tohiro Kusumi has been bringing in a whole lot of MSDOS filesystem updates; I can’t tell you the net effect but.I am sure they are useful if you are looking to share disk media; FAT is a sort of lowest common denominator.
A running description of activity related to DragonFly BSD.
Don’t forget that most (all?) UEFI/EFI boot partitions are FAT filesystems, so it’s possible these updates will affect that.
(There has been some discussion over on FreeBSD mailing lists related to this)