2.9BSD/usr/contrib/mh/strings/mailboxes.c

/*
 * This is where the user mailboxes are kept.  On our 11/70 they were
 * kept in each users $HOME directory.  This is where the VAX login
 * program is looking for them, as well as the old BELL mail.
 */

char    *mailboxes =      "/usr/spool/mail/";