A little investigation reveals another path: Go to the Tests page from the main web page:
<http://spamassassin.apache.org/tests.html>Select the latest SA version to see its list of tests. For a given test (AKA rule) click its Wiki link on the right. Either a descriptive page already exists, or you'll be presented with the option to create a new one. If the latter, select the RuleDescriptionTemplate from the list of templates, edit as needed, and save.
