DMARC with amavis+spamassassin

[John Fawcett]

Hi

I have a working installation of amavis 2.13.1 on Fedora 42 which 
currently is set to do DKIM signing and validation via spamassassin with 
DKIM plugin which adds the Authentication-Results header to inbound 
email. The relevant amavis setting is:

$enable_dkim_verification = 1

DMARC plugin is also apparently enabled as well as SPF and DKIM plugins 
and I see hits for SPF and DKIM rules in the X-Spam-Status header of 
incoming emails.

If I want to add DMARC validation. Can that only be done by adding an 
external checker like openDMARC? I was just wondering if there was a 
reason not to have validation within the SPF and DMARC plugins with 
amavis settings like:

$enable_spf_verification = 1

$enable_dmarc_verification = 1

(which don't currently exist as far as I know), updating the 
Authentication-Results headers for DKIM validation?

Thanks

John