Here is a list of all files with brief descriptions:

[detail level 1234]

sqmail-4.3.23
scripts
service
src
include
auto_break.h
auto_patrn.h
auto_qmail.h
auto_queue.h
auto_spawn.h
auto_split.h
auto_uids.h
auto_usera.h
base64.h
commands.h
constmap.h
control.h
date822fmt.h
datetime.h
dkim.h
dkimbase.h
dkimsign.h
dkimverify.h
dns.h
dnsdoe.h
dnsgettxt.h
exit.h
extra.h
fifo.h
fmtqfn.h
gfrom.h
global.h
headerbody.h
hfield.h
hier.h
hmac_md5.h
ipalloc.h
ipme.h
maildir.h
md5.h
mfrules.h
myctime.h
newfield.h
now.h
prioq.h
prot.h
qlx.h
qmail.h
qsutil.h
quote.h
rcpthosts.h
readsubdir.h
readwrite.h
received.h
recipients.h
sendtodo.h
sha1.h
sha256.h
smtpdlog.h
spf.h
srs2.h
strset.h
tcpto.h
tls_errors.h
tls_remote.h
tls_start.h
tls_timeoutio.h
token822.h
trigger.h
triggerpull.h
ucspitls.h
wildmat.h
auto-gid.c
auto-int.c
auto-int8.c
auto-str.c
auto-uid.c
base64.c
bouncesaying.c
chkshsgr.c
chkspawn.c
columnt.c
commands.c
condredirect.c
constmap.c
control.c
date822fmt.c
datetime.c
dkim.cpp
dkimbase.cpp
dkimsign.cpp
dkimverify.cpp
dns.c	DNS helpers: dns_ipplus, dns_ipalloc, dns_ip (IPv4+IPv6), dns_mxip
dns_tlsa.c
dnscname.c
dnsdoe.c
dnsfq.c
dnsip.c
dnsmxip.c
dnsptr.c
dnstlsa.c
dnstxt.c
except.c
fastforward.c
fifo.c
fmtqfn.c
forward.c
gfrom.c
headerbody.c
hfield.c
hier.c
hmac_md5.c
hostname.c
install.c
instcheck.c
ipalloc.c
ipme.c	Ipme_is4, ipme_is6, ipme_is46, ipme_init
ipmeprint.c
maildir.c
maildir2mbox.c
maildirmake.c
maildirwatch.c
matchup.c
md5c.c
mfrules.c
myctime.c
newaliases.c
newfield.c
newinclude.c
now.c
predate.c
preline.c
printforward.c
printmaillist.c
prioq.c
prot.c
qbiff.c
qmail-authuser.c	User authentication for qmail-smtpd/qmail-pop3d,bincimapd
qmail-badloadertypes.c
qmail-badmimetypes.c
qmail-clean.c
qmail-dkim.cpp
qmail-dksign.c
qmail-dkverify.c	Stub routine for DKIM signature verification and indication in received message
qmail-getpw.c
qmail-inject.c
qmail-ldapam.c
qmail-local.c
qmail-lspawn.c
qmail-mfrules.c
qmail-mrtg.c
qmail-newmrh.c
qmail-newu.c
qmail-pop3d.c
qmail-popup.c
qmail-postgrey.c
qmail-pw2u.c
qmail-qmaint.c
qmail-qmqpc.c
qmail-qmqpd.c
qmail-qmtpd.c	Requires sslserver
qmail-qread.c
qmail-queue.c
qmail-recipients.c
qmail-remote.c
qmail-rspawn.c
qmail-send.c
qmail-showctl.c
qmail-smtpam.c
qmail-smtpd.c	Requires sslserver or tcpserver
qmail-start.c
qmail-tcpok.c
qmail-tcpto.c
qmail-todo.c
qmail-vmailuser.c
qmail.c
qreceipt.c
qsutil.c
quote.c
rcpthosts.c
readsubdir.c
received.c
recipients.c	Functions recipients_init, recipients, recipients_parse, callapam
sendmail.c
setforward.c
setmaillist.c
sha1.c
sha256.c
smtpdlog.c
spawn.c
spf.c
spfdnsip.c
spfquery.c
splogger.c
srs2.c
srsforward.c	Forwarding mails with SRS enhanced addresss
srsreverse.c	Forwarding bounces with SRS enhanced addresss
strset.c
tai64nfrac.c
tcpto.c
tcpto_clean.c
tls_errors.c	Temp_tls* routines are used for error messges
tls_remote.c	Connection functions: tls_conn, tls_exit; verification functions: tls_certkey, tls_checkpeer, tls_fingerprint, tlsa_check; tls_destination, tls_domaincert dummy functions: tls_crlcheck
tls_start.c
tls_timeoutio.c
token822.c
trigger.c
triggerpull.c
trycpp.c
trydnsresolv.c
trydrent.c
tryflock.c
tryidn2.c
tryldap.c
trylsock.c
trymkffo.c
trynpbg1.c
tryqlibs.c
tryrsolv.c
trysalen.c
trysgact.c
trysgprm.c
tryshadow.c
tryshsgr.c
tryslib.c
tryspnam.c
trysysel.c
trysyslog.c
tryulong32.c
tryuserpw.c
tryutmp.c
tryvfork.c
trywaitp.c
wildmat.c