+# This subject rewrite is embedded in double-quoted strings. As such, some of
+# the items need more escaping than usual, otherwise \N becomes simply "N" and
+# the following \n a literal newline.
+RT_SUBJECT = Subject: ${if and {{first_delivery}{match {${sg{$rh_Subject:}{\\N\\n\[\\t \]\+\\N}{ }}}{\\N(?i)(.*?)\[?debian rt\]?[:\t ]*(.*)\\N}}} {$1$2}{$h_subject:}}