Index: /trunk/src/wp-includes/functions.php
===================================================================
--- /trunk/src/wp-includes/functions.php	(revision 63654)
+++ /trunk/src/wp-includes/functions.php	(revision 63655)
@@ -6403,4 +6403,6 @@
  * A return value of `3` means the file is not in the allowed files list.
  *
+ * A return value of `0` means no file was provided or processed.
+ *
  * Note that absolute POSIX paths such as `/etc/passwd` are *not* rejected, and
  * never have been. Callers that must reject them are responsible for their own