+replace $local_part with $local_part_data.
+
+Attempting to remove, in router or transport, a header name that ends with
+an asterisk (which is a standards-legal name) will now result in all headers
+named starting with the string before the asterisk being removed. We recommend
+staying away from such names, if they are private ones (and in case of future
+enhancements, alao header names that look like REs).