- * Rename the file so that its filename ends with the sequence ":2,"
- * followed by zero or more of the following single-character flags
- * (in ASCII order):
+ * 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.
+ *
+ * If the filename is in a maildir directory, rename the file so that
+ * its filename ends with the sequence ":2," followed by zero or more
+ * of the following single-character flags (in ASCII order):