Still more info:
qmail-showctl shows:
qmail home directory: /var/qmail.
user-ext delimiter: -.
paternalism (in decimal): 2.
silent concurrency limit: 120.
subdirectory split: 23.
user ids: 501, 502, 503, 0, 504, 505, 506, 507.
group ids: 501, 502.
badmailfrom: (Default.) Any MAIL FROM is...