The "pop3d" command:

Usage: fossil pop3d [OPTIONS] REPOSITORY

Begin a POP3 conversation with a client using stdin/stdout using the mailboxes stored in REPOSITORY.

If launched as root, the process first enters a chroot jail using the directory of REPOSITORY as root, then drops all privileges and assumes the user and group of REPOSITORY before reading any content off of the wire.

--logdir

DIR Each pop3d session creates a new logfile in the directory DIR and records a transcript of the session there. The logfile is opened before entering the chroot jail.