-If a record exists, the result field is either ccache_accept or ccache_reject.
-The other fields, however, (which are only relevant to domain records) may also
-contain ccache_unknown if that particular test has not been done.
+If a record exists, the result field is either ccache_accept or ccache_reject,
+or, for a domain record only, ccache_reject_mfnull when MAIL FROM:<> was
+rejected. The other fields, however, (which are only relevant to domain
+records) may also contain ccache_unknown if that particular test has not been
+done.