opensmtpd-extras-experimental 5.7.1-3.1 (s390x binary) in ubuntu artful

 This package provides experimental addons for OpenSMTPD. Using these may
 cause your OpenSMTPD installation to become unstable, insecure, or worse.
 Proceed with caution!
 .
 Please see each for a description of additional dependencies.
  * Filters:
    + clamav: filter mail through clamd [clamav-daemon]
    + dkim-signer: add DKIM signatures to headers
    + dnsbl: perform DNSBL checks
    + monkey: randomly accept mail with a probability of 70%
    + pause: pause on new connections to avoid "slamming" attacks
    + regex: filter mail using regex
    + spamassassin: filter mail through SpamAssassin's spamd [spamassassin]
    + trace: trace SMTP sessions
 This package does not yet provide the language bindings (Python, Perl, Lua,
 etc.) for implementing additional filters.