grep -l CONTENT /usr/share/spamassassin/* <nada>
So where does it come from?
did you try the other directories that rules are parsed from? It looks like it's a custom rule that someone, somewhere is using.
grep CONTENT_TYPE_MULTIPART /etc/mail/spamassassin/*
grep CONTENT_TYPE_MULTIPART ~/.spamassassin/user_prefs
I checked my SA archive, which covers 20 versions of SA from sa 1.5 to sa 2.63, plus a 2.70 cvs snapshot from 12/9/2004. It's never been a part of the standard ruleset.
