spamAssassin - more verbose explanations required

[completerookie]

I need to get a much better understanding of the spamAssassin test meanings
example
MISSING_MIMEOLE Message has X-MSMail-Priority, but no X-MimeOLE
PRIORITY_NO_NAME Message has priority, but no user agent name

I can read the brief meaning, but sometimes, I need to understand a lot more about why its failed the test

I'm NOT looking for the meanings of these particular examples, just a good web page that explains all the meanings.

can anyone point me to the more verbose descriptions of the test phrases please