courier-filter-perl binary package in Ubuntu Focal arm64

 Courier::Filter implements the Courier MTA's courierfilter interface as a
 framework for mail filter modules. Authors of filter modules can concentrate
 on writing the actual filter logic without having to care about the usual
 low-level details of the courierfilter interface. Logging to various
 facilities is also supported.
 .
 Courier::Filter allows multiple filter modules to be installed in stacked and
 hierarchically grouped configurations. Also, modules' polarity can be
 reversed, so some modules can be used for explicitly accepting messages while
 others are used in the traditional way for rejecting messages.
 .
 The following filter modules are included:
   * BlankBody: matching of blank bodies (a stupid spammer symptom)
   * DNSBL: matching of calling MTA's IP address against DNS black-lists
   * SPF: authentication of sender addresses in inbound messages
   * SPFout: authentication of sender addresses in outbound messages
   * Envelope: matching of RFC 2821 message envelope fields
   * Header: matching of RFC 2822 message header fields
   * FakeDate: detection of implausible and malformed date header fields
   * ClamAVd: malware detection using the ClamAV scanner
   * SpamAssassin: spam detection using SpamAssassin
   * Parts: matching of MIME parts and ZIP archive contents
   * SendCopy: sending message copies to additional recipients

Source package