-The search conditions take the form of a single letter followed by a
-space and a regexp, which can itself contain spaces. If the condition
-is prefaced by the character "!" it is negated, and has to be false
-for a mail to be selected.
+The search conditions take the form of a key which is a single letter,
+followed by a space and a regexp, which can itself contain spaces. If
+the condition is prefaced by the character "!" it is negated, and has
+to be false for a mail to be selected.
+
+The time-based conditions use as reference the time indicated in the
+heading From line, and not in the Date: field.