For FreeBSD 7.0 the majority of ZFS was in src/sys/contrib/opensolaris/uts/common/fs/zfs/ with src/sys/modules/zfs/ just having a makefile. For 7.1 ZFS is in src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/ and DTrace (which wasn't in 7.0) is in src/sys/cddl/contrib/opensolaris/uts/common/dtrace/. The copyright file is out of date anyway, since the paths have changed, so maybe they are including ZFS and DTrace now - the source tarball still has src/sys/cddl, but I can't find the resulting kernel packages to check.
As for CDDL being non-free, most of those results are Qt-style GPL license exceptions, with the notable exception of star, which is by Jörg "cdrecord" Schilling. The changelog says '* Disable GPL incompatible "zfs"' so maybe that's their reason.
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