And aren't there a bunch of newer ZFS features that Oracle has implemented that are not OSS? So, those are known only in documentation?
What the FOSS community has done is to add "feature flags" to ZFS instead of constantly bumping the version number. So encryption is a feature on top of zfs, but the encryption introduced in FreeNAS for ZFS isn't the same as the encryption in Oracle's zpool v30.
I've been runnning MacZFS for years, but it's currently way behind at zpool version 8, zfs version 2. At one point I put a FreeBSD machine in the basement, with plans to stream snapshot diffs for backup, but the version mismatches prevented me from doing this in a smart (zfs-based, rather than rsync-based) way.
Looks like this central coordination point ought to help the porting of features/versions from the Linux branch to the Mac branch.
Regarding OpenZFS, I thought it was quite surprising that the FreeBSD version wasn't used as a basis for a port, I imagined they had more in common.