--- a/src/rev.cpp.in	Sun Oct 21 12:45:43 2007 +0000
+++ b/src/rev.cpp.in	Sun Oct 21 14:59:05 2007 +0000
@@ -1,4 +1,44 @@
+/* $Id$ */
+
+/** @file rev.cpp Autogenerated file with the revision and such of OpenTTD. */
+
+#include "stdafx.h"
+
+/**
+ * The text version of OpenTTD's revision.
+ * This will be either "<major>.<minor>.<build>[-RC<rc>]",
+ * "r<revision number>[M][-<branch>]" or "norev000".
+ *
+ * The major, minor and build are the numbers that describe releases of
+ * OpenTTD (like 0.5.3). "-RC" is used to flag release candidates.
+ *
+ * The revision number is fairly straight forward. The M is to show that
+ * the binary is made from modified source code. The branch shows the
+ * branch the revision is of and will not be there when it is trunk.
+ *
+ * norev000 is for non-releases that are made on systems without
+ * subversion or sources that are not a checkout of subversion.
+ */
 extern const char _openttd_revision[] = "@@VERSION@@";
+
+/**
+ * The NewGRF revision of OTTD:
+ * bits  meaning.
+ * 28-31 major version
+ * 24-27 minor version
+ * 20-23 build
+ *    19 1 if it is a release, 0 if it is not.
+ *  0-18 revision number; 0 for releases and when the revision is unknown.
+ *
+ * The 19th bit is there so the development/betas/alpha, etc. leading to a
+ * final release will always have a lower version number than the released
+ * version, thus making comparisions on specific revisions easy.
+ */
+uint32 _openttd_newgrf_version = 0 << 28 | 6 << 24 | 0 << 20 | 0 << 19 | (@@REVISION@@ & ((1 << 19) - 1));
+
 #ifdef __MORPHOS__
+/**
+ * Variable used by MorphOS to show the version.
+ */
 extern const char morphos_versions_tag[] = "\\0$VER: OpenTTD @@VERSION@@ (@@DATE@@)  OpenTTD Team [MorphOS, PowerPC]";
 #endif