diff --git a/dtool/Version.cmake b/dtool/Version.cmake
index a9ca6c57b0..69efa2477c 100644
--- a/dtool/Version.cmake
+++ b/dtool/Version.cmake
@@ -1,52 +1,90 @@
-## Panda Version Information ##
+# This file defines the current version number for Panda. It is read
+# by the top CMakeLists.txt, which puts it in the global namespace for
+# all CMake scripts for Panda.
+
 set(PANDA_VERSION "1.9.0" CACHE STRING
   "Use dots to separate the major, minor, and sequence numbers.")
-set(PANDA_OFFICIAL_VERSION FALSE CACHE BOOL
-  "If on, signifies this is a tagged release rather than a repository snapshot.
-Scripts that generate source tarballs and/or binary releases for
-distribution should explicitly set this to true.")
-set(PANDA_DISTRIBUTOR "homebuilt" CACHE STRING
+
+option(PANDA_OFFICIAL_VERSION
+  "This variable will be defined to false in the CVS repository, but
+scripts that generate source tarballs and/or binary releases for
+distribution, by checking out Panda from an official CVS tag,
+should explictly set this to true. When false, it indicates that
+the current version of Panda was checked out from CVS, so it may
+not be a complete representation of the indicated version."
+  OFF)
+
+set(PANDA_DISTRIBUTOR homebuilt CACHE STRING
   "This string is reported verbatim by PandaSystem::get_distributor().
-It should be set by whoever provides a particular distribution of Panda.
-If you build your own Panda, leave this unchanged.")
+It should be set by whoever provides a particular distribution of
+Panda. If you build your own Panda, leave this unchanged.")
 
-set(PANDA_PLUGIN_VERSION "1.1.0" CACHE STRING
-  "We also define a version for the Panda3D plugin/runtime. This is an
-independent version number from PANDA_VERSION or PANDA_PACKAGE_VERSION,
-because it is anticipated that this plugin code, once settled,
-will need to be updated much less frequently than Panda itself.")
-set(P3D_PLUGIN_VERSION "${PANDA_PLUGIN_VERSION}")
-set(P3D_COREAPI_VERSION "${P3D_PLUGIN_VERSION}.1")
+set(PANDA_PACKAGE_VERSION CACHE STRING
+  "This string is used to describe the Panda3D \"package\" associated
+with this current build of Panda. It should increment with major
+and minor version changes, but not sequence (or \"bugfix\") changes.
+It should be unique for each unique distributor. The default is
+the empty string, which means this build does not precisely match
+any distributable Panda3D packages. If you are making a Panda3D
+build which you will be using to produce a distributable Panda3D
+package, you should set this string appropriately.")
+
+set(P3D_PLUGIN_VERSION "1.0.4" CACHE STRING
+  "We also define a version for the Panda3D plugin/runtime,
+i.e. nppanda3d.dll, p3dactivex.ocx, and panda3d.exe. This is an
+independent version number from PANDA_VERSION or
+PANDA_PACKAGE_VERSION, because it is anticipated that this plugin
+code, once settled, will need to be updated much less frequently
+than Panda itself.")
+
+set(P3D_COREAPI_VERSION "${P3D_PLUGIN_VERSION}.1" CACHE STRING
+  "Finally, there's a separate version number for the Core API. At
+first, we didn't believe we needed a Core API version number, but
+in this belief we were naive. This version number is a little less
+strict in its format requirements than P3D_PLUGIN_VERSION, above,
+and it doesn't necessarily consist of a specific number of
+integers, but by convention it will consist of four integers, with
+the first three matching the plugin version, and the fourth integer
+being incremented with each new Core API revision.")
 
 
-## Parse Panda3D Subversions ##
+# Separate the Panda3D version into its three components.
 string(REPLACE "." ";" PANDA_VERSION_LIST "${PANDA_VERSION}")
 list(GET PANDA_VERSION_LIST 0 PANDA_MAJOR_VERSION)
 list(GET PANDA_VERSION_LIST 1 PANDA_MINOR_VERSION)
 list(GET PANDA_VERSION_LIST 2 PANDA_SEQUENCE_VERSION)
 
+# The version gets a "c" at the end if it's not an official one.
 if(PANDA_OFFICIAL_VERSION)
-	set(PANDA_VERSION_STR "${PANDA_VERSION}c")
+  set(VERSION_SUFFIX "")
 else()
-	set(PANDA_VERSION_STR "${PANDA_VERSION}c")
+  set(VERSION_SUFFIX "c")
 endif()
 
+set(PANDA_VERSION_STR "${PANDA_VERSION}c")
+
+# This symbol is used to enforce ABI incompatibility between
+# major versions of Panda3D.
 set(PANDA_VERSION_SYMBOL panda_version_${PANDA_MAJOR_VERSION}_${PANDA_MINOR_VERSION})
 
+# The Panda version as a number, with three digits reserved
+# for each component.
 math(EXPR PANDA_NUMERIC_VERSION "${PANDA_MAJOR_VERSION}*1000000 + ${PANDA_MINOR_VERSION}*1000 + ${PANDA_SEQUENCE_VERSION}")
 
-
-## Parse Plugin-framework Subversions ##
+# Separate the plugin version into its three components.
 string(REPLACE "." ";" P3D_PLUGIN_VERSION_LIST "${P3D_PLUGIN_VERSION}")
 list(GET P3D_PLUGIN_VERSION_LIST 0 P3D_PLUGIN_MAJOR_VERSION)
 list(GET P3D_PLUGIN_VERSION_LIST 1 P3D_PLUGIN_MINOR_VERSION)
 list(GET P3D_PLUGIN_VERSION_LIST 2 P3D_PLUGIN_SEQUENCE_VERSION)
 
+set(P3D_PLUGIN_VERSION_STR "${P3D_PLUGIN_VERSION}${VERSION_SUFFIX}")
+
+# The plugin version as dot-delimited integer quad, according to MS
+# conventions for DLL version numbers.
 if(PANDA_OFFICIAL_VERSION)
-	set(P3D_PLUGIN_VERSION_STR "${P3D_PLUGIN_VERSION}")
-	set(P3D_PLUGIN_DLL_DOT_VERSION "${P3D_PLUGIN_VERSION_STR}.1000")
+  set(P3D_PLUGIN_DLL_DOT_VERSION "${P3D_PLUGIN_VERSION}.1000")
 else()
-	set(P3D_PLUGIN_VERSION_STR "${P3D_PLUGIN_VERSION}c")
-	set(P3D_PLUGIN_DLL_DOT_VERSION "${P3D_PLUGIN_VERSION}.0")
+  set(P3D_PLUGIN_DLL_DOT_VERSION "${P3D_PLUGIN_VERSION}.0")
 endif()
+# The same thing as a comma-delimited quad.
 string(REPLACE "." "," P3D_PLUGIN_DLL_COMMA_VERSION "${P3D_PLUGIN_DLL_DOT_VERSION}")
diff --git a/dtool/src/dtoolutil/checkPandaVersion.cxx.cmake b/dtool/src/dtoolutil/checkPandaVersion.cxx.cmake
index db059b6870..f268bfbd21 100644
--- a/dtool/src/dtoolutil/checkPandaVersion.cxx.cmake
+++ b/dtool/src/dtoolutil/checkPandaVersion.cxx.cmake
@@ -16,6 +16,6 @@
  *  Generated automatically by CMake.
  ***************************** DO NOT EDIT *************************/
 
-# include "dtoolbase.h"
+#include "dtoolbase.h"
 
 EXPCL_DTOOL int @PANDA_VERSION_SYMBOL@ = 0;
diff --git a/dtool/src/dtoolutil/checkPandaVersion.h.cmake b/dtool/src/dtoolutil/checkPandaVersion.h.cmake
index de76900fc0..583f3b00f6 100644
--- a/dtool/src/dtoolutil/checkPandaVersion.h.cmake
+++ b/dtool/src/dtoolutil/checkPandaVersion.h.cmake
@@ -26,14 +26,14 @@
    DLL; but the system linker will prevent the DLL from loading with
    an undefined symbol. */
 
-# include "dtoolbase.h"
+#include "dtoolbase.h"
 
 extern EXPCL_DTOOL int @PANDA_VERSION_SYMBOL@;
 
-# ifndef WIN32
+#ifndef WIN32
 /* For Windows, exporting the symbol from the DLL is sufficient; the
    DLL will not load unless all expected public symbols are defined.
    Other systems may not mind if the symbol is absent unless we
    explictly write code that references it. */
 static int check_panda_version = @PANDA_VERSION_SYMBOL@;
-# endif
+#endif
diff --git a/dtool/src/dtoolutil/pandaVersion.h.cmake b/dtool/src/dtoolutil/pandaVersion.h.cmake
index 19321d09a8..350a229e4e 100644
--- a/dtool/src/dtoolutil/pandaVersion.h.cmake
+++ b/dtool/src/dtoolutil/pandaVersion.h.cmake
@@ -18,7 +18,7 @@
 
    Do NOT attempt to edit the version number in this file.  This is a
    generated file, and your changes to this file will not persist.  To
-   increment the version number, modify dtool/PandaVersion.pp and
+   increment the version number, modify dtool/PandaVersion.cmake and
    re-run ppremake.
 
  ***************************** DO NOT EDIT *************************/
@@ -70,8 +70,8 @@
 
 #if HAVE_P3D_PLUGIN
 /* Similar definitions for the plugin versioning, if in use. */
-#define P3D_PLUGIN_MAJOR_VERSION "@P3D_PLUGIN_MAJOR_VERSION@"
-#define P3D_PLUGIN_MINOR_VERSION "@P3D_PLUGIN_MINOR_VERSION@"
-#define P3D_PLUGIN_SEQUENCE_VERSION "@P3D_PLUGIN_SEQUENCE_VERSION@"
+#define P3D_PLUGIN_MAJOR_VERSION @P3D_PLUGIN_MAJOR_VERSION@
+#define P3D_PLUGIN_MINOR_VERSION @P3D_PLUGIN_MINOR_VERSION@
+#define P3D_PLUGIN_SEQUENCE_VERSION @P3D_PLUGIN_SEQUENCE_VERSION@
 #define P3D_COREAPI_VERSION_STR "@P3D_COREAPI_VERSION_STR@"
 #endif