/lib/udev/rules.d/90-zfs.rules is in zfsutils-linux 0.7.5-1ubuntu15.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 | SUBSYSTEM!="block|misc", GOTO="zfs_end"
ACTION!="add|change", GOTO="zfs_end"
ENV{ID_FS_TYPE}=="zfs", RUN+="/sbin/modprobe zfs"
ENV{ID_FS_TYPE}=="zfs_member", RUN+="/sbin/modprobe zfs"
KERNEL=="null", SYMLINK+="root"
SYMLINK=="null", SYMLINK+="root"
SUBSYSTEM=="misc", KERNEL=="zfs", MODE="0666"
LABEL="zfs_end"
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