It fits poorly with limited amount of checks that are (and will be)
implemented in maddy.
Advanced filtering that requires "spam score" logic should be performed
by external software such as rspamd. At this point duplicating that
logic in maddy makes no sense, since it is highly problematic to
integrate it with external software.
Mailing lists break DKIM signatures by modifing Subject and other header
fields. They are supposed to either include their own DKIM signature
and/or ARC (RFC 8617) seal.
Now modules are documented in separate man pages depending on their
main purpose. This generally keeps things more organised than with
one huge maddy.conf(5) page to document everything.
