Quotation marks in smtpd.conf

[Paul Pace]

When is it required for using quotation marks in smtpd.conf?
I was just noticing smtpd.conf(5) has examples using quotation marks, 
such as:

action "local_mail" mbox alias <aliases>
filter "dkimsign" proc-exec "filter-dkimsign -d <domain> -s <selector> \
        -k /etc/mail/dkim/private.key" user _dkimsign group _dkimsign

But then I noticed the package readme for dkimsign has the following 
examples:

filter dkimsign_rsa proc-exec "filter-dkimsign -d <domain> -s <selector> 
-k /etc/mail/dkim/private.rsa.key" user _dkimsign group _dkimsign
filter dkimsign chain { dkimsign_rsa, dkimsign_ed25519 }

So I went through and removed all quotation marks in my smtpd.conf and 
the only ones that seem to be needed are the ones around pki related 
locations.

Thank you,


Paul