It might be less confusing if attempts to read root's mail, e.g. with mail(1), would be guided further to the mailbox of the user who actually receives that by a single message archived in a (%ghost) /var/spool/mail/root; contents draft:

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From: root@localhost
Subject: mail alias reminder

    Dear myself,
this is to remind that root's mail is redirected to the first unprivileged
user customarily created during installation so as to avoid privileged MUA.
In case the "first user" isn't clear enough, let's figure out for sure:

  grep ^root: /etc/aliases

P.S. be prudent and careful!
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