+// Keep the changes documented in the Customization manual.
+//
+// If you change this format, then you MUST also make sure that
+// your changes do not invalidate the hardcoded layout file in
+// LayoutFile.cpp. Additions will never do so, but syntax changes
+// could. See LayoutFileList::addEmptyClass() and, especially, the
+// definition of the layoutpost string.
+// You should also run (or ask someone who has bash to run) the
+// development/updatelayouts.sh script, to update the format of
+// all of our layout files.
+//
+int const LAYOUT_FORMAT = 28;
+