The open-source IllumOS code in FreeBSD had fallen behind Linux ZoL (ZFS-On-Linux). FreeBSD adopted ZoL to keep up with new bugfixes, enhancements, etc.
>>The OpenZFS project brings together developers from the Linux, FreeBSD, illumos, MacOS, and Windows platforms. OpenZFS is supported by a wide range of companies.
Wrong, there is no ZoL anymore "just" OpenZFS:
https://openzfs.org/wiki/Main_Page
>>The OpenZFS project brings together developers from the Linux, FreeBSD, illumos, MacOS, and Windows platforms. OpenZFS is supported by a wide range of companies.
And again ZFS is NOT part of Linux.