>this version is based on FreeBSD svn r315983"
For anyone interested, I believe these are the relevant CDDL dtrace/zfs components from that revision of FreeBSD, from early 2017: https://svnweb.freebsd.org/base/head/sys/cddl/?pathrev=31598...
Nice! Good job Netbsd!
This makes NetBSD the 6th OpenZFS platform, after Illumos, FreeBSD, Linux, Mac OS X and OSv. The 7th if you include the under development Windows port:
https://github.com/openzfsonwindows/ZFSin