Correct the root is located in the dataset zroot/ROOT/default, all mount points that are not specified separately, such as zroot/var, will depend on and be located in zroot/ROOT/default.I have to double check, but I am not sure, the /root home folder, where GPG keys are stored is that located under zroot/ROOT/default? Or does that come via zroot , the highest level ...
zfs list -o name,mountpoint