How To Analyse PN SPAM Filter Headers

[#1]

I received an email that ended up in my SPAM folder. It was from a known correspondent and I was somewhat surprised to find it there.
Looking at the headers I'd like to understand how it was scored. Is there any information on this, or better still a tool that will read the headers?

[#2]

As far as I'm aware only a basic outline has been published on the Cloudmark spam system and nothing on what the analysis means. Very occasionally not-spam emails do get tagged, one assumes because their fingerprints match something in the Cloudmark database.
For such messages you could help to improve the accuracy of the detection system by logging into webmail and viewing the Spam (Junk) folder. Highlight the incorrectly identified message and click the "Not spam" button to report it to Cloudmark for analysis by their technical team. The message would also be moved to your Inbox though any [SPAM] tag would remain.