- * If the filename is not in a maildir directory, do nothing.
- * (A maildir directory is determined as a directory named "new" or
- * "cur".)
+ * If the filename is not in a maildir directory, do nothing. (A
+ * maildir directory is determined as a directory named "new" or
+ * "cur".) Similarly, if the filename has invalid maildir info,
+ * (repeated or outof-ASCII-order flag characters after ":2,"), then
+ * do nothing.