diff --git a/CMakeLists.txt b/CMakeLists.txt
index fd17283f77..1bacca1a48 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -820,12 +820,6 @@ else()
   OCCT_CHECK_AND_UNSET ("3RDPARTY_DOT_EXECUTABLE")
 endif()
 
-# ExpToCasExe
-if (EMSCRIPTEN)
-  list (REMOVE_ITEM BUILD_TOOLKITS TKExpress)
-  list (REMOVE_ITEM BUILD_TOOLKITS ExpToCasExe)
-endif()
-
 # bison
 if (BUILD_YACCLEX)
   OCCT_INCLUDE_CMAKE_FILE ("adm/cmake/bison")
diff --git a/adm/MODULES b/adm/MODULES
index f471f8dc8d..235c30595d 100644
--- a/adm/MODULES
+++ b/adm/MODULES
@@ -3,5 +3,6 @@ ModelingData TKG2d TKG3d TKGeomBase TKBRep
 ModelingAlgorithms TKGeomAlgo TKTopAlgo TKPrim TKBO TKBool TKHLR TKFillet TKOffset TKFeat TKMesh TKXMesh TKShHealing
 Visualization TKService TKV3d TKOpenGl TKOpenGles TKMeshVS TKIVtk TKD3DHost
 ApplicationFramework TKCDF TKLCAF TKCAF TKBinL TKXmlL TKBin TKXml TKStdL TKStd TKTObj TKBinTObj TKXmlTObj TKVCAF
-DataExchange TKXDE TKXSBase TKSTEPBase TKSTEPAttr TKSTEP209 TKSTEP TKIGES TKXCAF TKXDEIGES TKXDESTEP TKSTL TKVRML TKXmlXCAF TKBinXCAF TKRWMesh TKXDECascade TKExpress ExpToCasExe
+DataExchange TKXDE TKXSBase TKSTEPBase TKSTEPAttr TKSTEP209 TKSTEP TKIGES TKXCAF TKXDEIGES TKXDESTEP TKSTL TKVRML TKXmlXCAF TKBinXCAF TKRWMesh TKXDECascade
 Draw TKDraw TKTopTest TKOpenGlTest TKOpenGlesTest TKD3DHostTest TKViewerTest TKXSDRAW TKDCAF TKXDEDRAW TKTObjDRAW TKQADraw TKIVtkDraw DRAWEXE
+DETools TKExpress ExpToCasExe
diff --git a/adm/cmake/occt_toolkit.cmake b/adm/cmake/occt_toolkit.cmake
index 61f195f82f..c9399159f1 100644
--- a/adm/cmake/occt_toolkit.cmake
+++ b/adm/cmake/occt_toolkit.cmake
@@ -70,6 +70,16 @@ foreach (OCCT_PACKAGE ${USED_PACKAGES})
     OCCT_ORIGIN_AND_PATCHED_FILES ("${RELATIVE_SOURCES_DIR}/${OCCT_PACKAGE}" "*[.]lex" SOURCE_FILES_FLEX)
     list (LENGTH SOURCE_FILES_FLEX SOURCE_FILES_FLEX_LEN)
 
+    # remove old general version of FlexLexer
+    if (EXISTS ${CMAKE_SOURCE_DIR}/${RELATIVE_SOURCES_DIR}/FlexLexer/FlexLexer.h)
+      message (STATUS "Info: remove old FLEX header file: ${CMAKE_SOURCE_DIR}/${RELATIVE_SOURCES_DIR}/FlexLexer/FlexLexer.h")
+      file(REMOVE ${CMAKE_SOURCE_DIR}/${RELATIVE_SOURCES_DIR}/FlexLexer/FlexLexer.h)
+    endif()
+    # install copy of FlexLexer.h locally to allow further building without flex
+    if (FLEX_INCLUDE_DIR AND EXISTS "${FLEX_INCLUDE_DIR}/FlexLexer.h")
+      configure_file("${FLEX_INCLUDE_DIR}/FlexLexer.h" "${CMAKE_SOURCE_DIR}/${RELATIVE_SOURCES_DIR}/FlexLexer/FlexLexer.h" @ONLY NEWLINE_STYLE LF)
+    endif()
+
     # bison files
     OCCT_ORIGIN_AND_PATCHED_FILES ("${RELATIVE_SOURCES_DIR}/${OCCT_PACKAGE}" "*[.]yacc" SOURCE_FILES_BISON)
     list (LENGTH SOURCE_FILES_BISON SOURCE_FILES_BISON_LEN)
@@ -107,21 +117,11 @@ foreach (OCCT_PACKAGE ${USED_PACKAGES})
             endif()
           endforeach()
 
-          if (EXISTS ${FLEX_BISON_TARGET_DIR}/FlexLexer.h)
-            message (STATUS "Info: remove old FLEX header file: ${FLEX_BISON_TARGET_DIR}/FlexLexer.h")
-            file(REMOVE ${FLEX_BISON_TARGET_DIR}/FlexLexer.h)
-          endif()
-
           file (STRINGS "${CURRENT_FLEX_FILE}" FILE_FLEX_CONTENT)
           foreach (FILE_FLEX_CONTENT_LINE ${FILE_FLEX_CONTENT})
             string (REGEX MATCH "%option c\\+\\+" CXX_FLEX_LANGUAGE_FOUND ${FILE_FLEX_CONTENT_LINE})
             if (CXX_FLEX_LANGUAGE_FOUND)
               set (FLEX_OUTPUT_FILE_EXT "cxx")
-
-              # install copy of FlexLexer.h locally to allow further building without flex
-              if (FLEX_INCLUDE_DIR AND EXISTS "${FLEX_INCLUDE_DIR}/FlexLexer.h")
-                configure_file("${FLEX_INCLUDE_DIR}/FlexLexer.h" "${FLEX_BISON_TARGET_DIR}/FlexLexer.h" @ONLY NEWLINE_STYLE LF)
-              endif()
             endif()
           endforeach()
           set (BISON_OUTPUT_FILE ${CURRENT_BISON_FILE_NAME}.tab.${BISON_OUTPUT_FILE_EXT})
diff --git a/adm/cmake/vardescr.cmake b/adm/cmake/vardescr.cmake
index 8212a0308b..1d7631b7dd 100644
--- a/adm/cmake/vardescr.cmake
+++ b/adm/cmake/vardescr.cmake
@@ -116,6 +116,7 @@ endmacro()
 
 BUILD_MODULE_MESSAGE (BUILD_MODULE_ApplicationFramework "ApplicationFramework")
 BUILD_MODULE_MESSAGE (BUILD_MODULE_DataExchange         "DataExchange")
+BUILD_MODULE_MESSAGE (BUILD_MODULE_DETools              "DETools")
 BUILD_MODULE_MESSAGE (BUILD_MODULE_Draw                 "Draw")
 BUILD_MODULE_MESSAGE (BUILD_MODULE_FoundationClasses    "FoundationClasses")
 BUILD_MODULE_MESSAGE (BUILD_MODULE_ModelingAlgorithms   "ModelingAlgorithms")
diff --git a/adm/scripts/android_build.bat b/adm/scripts/android_build.bat
index ce1aa67bd2..247d23cde7 100644
--- a/adm/scripts/android_build.bat
+++ b/adm/scripts/android_build.bat
@@ -33,6 +33,7 @@ set "BUILD_ModelingAlgorithms=ON"
 set "BUILD_Visualization=ON"
 set "BUILD_ApplicationFramework=ON"
 set "BUILD_DataExchange=ON"
+set "BUILD_DETools=OFF"
 
 rem Optional 3rd-party libraries to enable
 set "USE_FREETYPE=ON"
@@ -166,6 +167,7 @@ if ["%toCMake%"] == ["1"] (
  -D BUILD_MODULE_Visualization:BOOL="%BUILD_Visualization%" ^
  -D BUILD_MODULE_ApplicationFramework:BOOL="%BUILD_ApplicationFramework%" ^
  -D BUILD_MODULE_DataExchange:BOOL="%BUILD_DataExchange%" ^
+ -D BUILD_MODULE_DETools:BOOL="OFF" ^
  -D BUILD_MODULE_Draw:BOOL="OFF" ^
  -D BUILD_DOC_Overview:BOOL="OFF" ^
  -D USE_FREETYPE:BOOL="%USE_FREETYPE%" ^
diff --git a/adm/scripts/android_custom.bat.template b/adm/scripts/android_custom.bat.template
index 45881c6d40..9c1bd7beab 100644
--- a/adm/scripts/android_custom.bat.template
+++ b/adm/scripts/android_custom.bat.template
@@ -27,6 +27,7 @@ rem set "BUILD_ModelingAlgorithms=ON"
 rem set "BUILD_Visualization=ON"
 rem set "BUILD_ApplicationFramework=ON"
 rem set "BUILD_DataExchange=ON"
+rem set "BUILD_MODULE_DETools=OFF"
 
 rem Optional 3rd-party libraries to enable
 rem set "USE_RAPIDJSON=ON"
diff --git a/adm/scripts/cmake_custom.bat.template b/adm/scripts/cmake_custom.bat.template
index eabc8290b0..f2bbe81343 100644
--- a/adm/scripts/cmake_custom.bat.template
+++ b/adm/scripts/cmake_custom.bat.template
@@ -33,6 +33,7 @@ rem set BUILD_PATCH=
 
 rem set BUILD_MODULE_ApplicationFramework=ON
 rem set BUILD_MODULE_DataExchange=ON
+rem set BUILD_MODULE_DETools=OFF
 rem set BUILD_MODULE_Draw=ON
 rem set BUILD_MODULE_ModelingAlgorithms=ON
 rem set BUILD_MODULE_ModelingData=ON
diff --git a/adm/scripts/cmake_custom.sh.template b/adm/scripts/cmake_custom.sh.template
index 6ed63c7f13..e6e265df4d 100644
--- a/adm/scripts/cmake_custom.sh.template
+++ b/adm/scripts/cmake_custom.sh.template
@@ -26,6 +26,7 @@ FREETYPE_DIR="$OCCT3RDPARTY/freetype-2.7.1"
 
 #BUILD_MODULE_ApplicationFramework=ON
 #BUILD_MODULE_DataExchange=ON
+#BUILD_MODULE_DETools=OFF
 #BUILD_MODULE_Draw=ON
 #BUILD_MODULE_ModelingAlgorithms=ON
 #BUILD_MODULE_ModelingData=ON
diff --git a/adm/scripts/cmake_gen.bat b/adm/scripts/cmake_gen.bat
index f60e47b129..80f9600c62 100644
--- a/adm/scripts/cmake_gen.bat
+++ b/adm/scripts/cmake_gen.bat
@@ -28,6 +28,7 @@ set BUILD_FORCE_RelWithDebInfo=OFF
 
 set BUILD_MODULE_ApplicationFramework=ON
 set BUILD_MODULE_DataExchange=ON
+set BUILD_MODULE_DETools=OFF
 set BUILD_MODULE_Draw=ON
 set BUILD_MODULE_ModelingAlgorithms=ON
 set BUILD_MODULE_ModelingData=ON
@@ -62,6 +63,7 @@ cmake -G "%arch_compile%" ^
   -D BUILD_LIBRARY_TYPE:STRING=%BUILD_LIBRARY_TYPE% ^
   -D BUILD_MODULE_ApplicationFramework:BOOL=%BUILD_MODULE_ApplicationFramework% ^
   -D BUILD_MODULE_DataExchange:BOOL=%BUILD_MODULE_DataExchange% ^
+  -D BUILD_MODULE_DETools:BOOL=%BUILD_MODULE_DETools% ^
   -D BUILD_MODULE_Draw:BOOL=%BUILD_MODULE_Draw% ^
   -D BUILD_MODULE_FoundationClasses:BOOL=ON ^
   -D BUILD_MODULE_ModelingAlgorithms:BOOL=%BUILD_MODULE_ModelingAlgorithms% ^
diff --git a/adm/scripts/cmake_gen.sh b/adm/scripts/cmake_gen.sh
index 9c088715d2..feef7a07db 100755
--- a/adm/scripts/cmake_gen.sh
+++ b/adm/scripts/cmake_gen.sh
@@ -31,6 +31,7 @@ BUILD_ENABLE_FPE_SIGNAL_HANDLER=ON
 
 BUILD_MODULE_ApplicationFramework=ON
 BUILD_MODULE_DataExchange=ON
+BUILD_MODULE_DETools=OFF
 BUILD_MODULE_Draw=ON
 BUILD_MODULE_ModelingAlgorithms=ON
 BUILD_MODULE_ModelingData=ON
@@ -63,6 +64,7 @@ cmake -G "Unix Makefiles" \
   -D BUILD_LIBRARY_TYPE:STRING=$BUILD_LIBRARY_TYPE \
   -D BUILD_MODULE_ApplicationFramework:BOOL=$BUILD_MODULE_ApplicationFramework \
   -D BUILD_MODULE_DataExchange:BOOL=$BUILD_MODULE_DataExchange \
+  -D BUILD_MODULE_DETools:BOOL=$BUILD_MODULE_DETools \
   -D BUILD_MODULE_Draw:BOOL=$BUILD_MODULE_Draw \
   -D BUILD_MODULE_FoundationClasses:BOOL=ON \
   -D BUILD_MODULE_ModelingAlgorithms:BOOL=$BUILD_MODULE_ModelingAlgorithms \
diff --git a/adm/scripts/ios_build.sh b/adm/scripts/ios_build.sh
index ff222519a2..b9ada581b5 100755
--- a/adm/scripts/ios_build.sh
+++ b/adm/scripts/ios_build.sh
@@ -34,6 +34,7 @@ export BUILD_ModelingAlgorithms=ON
 export BUILD_Visualization=ON
 export BUILD_ApplicationFramework=ON
 export BUILD_DataExchange=ON
+export BUILD_DETools=OFF
 
 export USE_FREETYPE=ON
 export USE_FREEIMAGE=OFF
@@ -148,6 +149,7 @@ function buildArch {
   -D BUILD_MODULE_Visualization:BOOL="${BUILD_Visualization}" \
   -D BUILD_MODULE_ApplicationFramework:BOOL="${BUILD_ApplicationFramework}" \
   -D BUILD_MODULE_DataExchange:BOOL="${BUILD_DataExchange}" \
+  -D BUILD_MODULE_DETools:BOOL="${BUILD_DETools}" \
   -D BUILD_MODULE_Draw:BOOL="OFF" \
   -D BUILD_DOC_Overview:BOOL="OFF" \
     "$aCasSrc" 2>&1 | tee -a "$aLogFile"
diff --git a/adm/scripts/ios_custom.sh.template b/adm/scripts/ios_custom.sh.template
index c54624ebf6..4d4d13b485 100644
--- a/adm/scripts/ios_custom.sh.template
+++ b/adm/scripts/ios_custom.sh.template
@@ -20,6 +20,7 @@ export aDraco="$aSrcRoot/../3rdparty/draco-1.4.1-ios"
 #export BUILD_Visualization=ON
 #export BUILD_ApplicationFramework=ON
 #export BUILD_DataExchange=ON
+#export BUILD_DETools=OFF
 
 #export USE_RAPIDJSON=ON
 #export USE_DRACO=ON
diff --git a/adm/scripts/macos_build.sh b/adm/scripts/macos_build.sh
index b44fb1bec5..4cdaa8bddc 100755
--- a/adm/scripts/macos_build.sh
+++ b/adm/scripts/macos_build.sh
@@ -34,6 +34,7 @@ export BUILD_ModelingAlgorithms=ON
 export BUILD_Visualization=ON
 export BUILD_ApplicationFramework=ON
 export BUILD_DataExchange=ON
+export BUILD_DETools=OFF
 export BUILD_Draw=ON
 
 export USE_FREETYPE=ON
@@ -145,6 +146,7 @@ function buildArch {
   -D BUILD_MODULE_Visualization:BOOL="${BUILD_Visualization}" \
   -D BUILD_MODULE_ApplicationFramework:BOOL="${BUILD_ApplicationFramework}" \
   -D BUILD_MODULE_DataExchange:BOOL="${BUILD_DataExchange}" \
+  -D BUILD_MODULE_DETools:BOOL="${BUILD_DETools}" \
   -D BUILD_MODULE_Draw:BOOL="${BUILD_Draw}" \
   -D BUILD_DOC_Overview:BOOL="OFF" \
     "$aCasSrc" 2>&1 | tee -a "$aLogFile"
diff --git a/adm/scripts/macos_custom.sh.template b/adm/scripts/macos_custom.sh.template
index 740c24f640..637277aa91 100644
--- a/adm/scripts/macos_custom.sh.template
+++ b/adm/scripts/macos_custom.sh.template
@@ -19,6 +19,7 @@ export aDraco="$aSrcRoot/../3rdparty/draco-1.4.1-macos"
 #export BUILD_Visualization=ON
 #export BUILD_ApplicationFramework=ON
 #export BUILD_DataExchange=ON
+#export BUILD_DETools=OFF
 #export BUILD_Draw=ON
 
 #export USE_RAPIDJSON=ON
diff --git a/adm/scripts/mingw_build.bat b/adm/scripts/mingw_build.bat
index d66d339e5e..27e33625fa 100644
--- a/adm/scripts/mingw_build.bat
+++ b/adm/scripts/mingw_build.bat
@@ -32,6 +32,7 @@ set "BUILD_ModelingAlgorithms=ON"
 set "BUILD_Visualization=ON"
 set "BUILD_ApplicationFramework=ON"
 set "BUILD_DataExchange=ON"
+set "BUILD_DETools=OFF"
 set "BUILD_Draw=ON"
 
 rem Optional 3rd-party libraries to enable
@@ -155,6 +156,7 @@ if ["%toCMake%"] == ["1"] (
  -D BUILD_MODULE_Visualization:BOOL="%BUILD_Visualization%" ^
  -D BUILD_MODULE_ApplicationFramework:BOOL="%BUILD_ApplicationFramework%" ^
  -D BUILD_MODULE_DataExchange:BOOL="%BUILD_DataExchange%" ^
+ -D BUILD_MODULE_DETools:BOOL="%BUILD_DETools%" ^
  -D BUILD_MODULE_Draw:BOOL="%BUILD_Draw%" ^
  -D 3RDPARTY_TCL_DIR:PATH="%aTclTk%" ^
  -D 3RDPARTY_TCL_INCLUDE_DIR:FILEPATH="%aTclTk%/include" ^
diff --git a/adm/scripts/mingw_custom.bat.template b/adm/scripts/mingw_custom.bat.template
index 0a7f6c6750..67a5f5471f 100644
--- a/adm/scripts/mingw_custom.bat.template
+++ b/adm/scripts/mingw_custom.bat.template
@@ -22,6 +22,7 @@ rem set "BUILD_ModelingAlgorithms=ON"
 rem set "BUILD_Visualization=ON"
 rem set "BUILD_ApplicationFramework=ON"
 rem set "BUILD_DataExchange=ON"
+rem set "BUILD_DETools=OFF"
 rem set "BUILD_Draw=ON"
 
 rem set "USE_RAPIDJSON=ON"
diff --git a/adm/scripts/wasm_build.bat b/adm/scripts/wasm_build.bat
index 4ef9a61f73..7495b8079b 100644
--- a/adm/scripts/wasm_build.bat
+++ b/adm/scripts/wasm_build.bat
@@ -32,6 +32,7 @@ set "BUILD_ModelingAlgorithms=ON"
 set "BUILD_Visualization=ON"
 set "BUILD_ApplicationFramework=ON"
 set "BUILD_DataExchange=ON"
+set "BUILD_DETools=OFF"
 set "BUILD_Draw=OFF"
 
 rem Optional 3rd-party libraries to enable
@@ -175,6 +176,7 @@ if ["%toCMake%"] == ["1"] (
  -D BUILD_MODULE_Visualization:BOOL="%BUILD_Visualization%" ^
  -D BUILD_MODULE_ApplicationFramework:BOOL="%BUILD_ApplicationFramework%" ^
  -D BUILD_MODULE_DataExchange:BOOL="%BUILD_DataExchange%" ^
+ -D BUILD_MODULE_DETools:BOOL="%BUILD_DETools%" ^
  -D BUILD_MODULE_Draw:BOOL="%BUILD_Draw%" ^
  -D BUILD_DOC_Overview:BOOL="OFF" ^
  -D USE_FREETYPE:BOOL="%USE_FREETYPE%" ^
diff --git a/adm/scripts/wasm_build.sh b/adm/scripts/wasm_build.sh
index b02a3080c1..b4f123da7e 100755
--- a/adm/scripts/wasm_build.sh
+++ b/adm/scripts/wasm_build.sh
@@ -20,6 +20,7 @@ export BUILD_ModelingAlgorithms=ON
 export BUILD_Visualization=ON
 export BUILD_ApplicationFramework=ON
 export BUILD_DataExchange=ON
+export BUILD_DETools=OFF
 
 if [ -f "${aScriptDir}/wasm_custom.sh" ] ; then
   . "${aScriptDir}/wasm_custom.sh"
@@ -74,6 +75,7 @@ echo cmake -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE:FILEPATH="${aToolchain}" \
 -DBUILD_MODULE_Visualization:BOOL="${BUILD_Visualization}" \
 -DBUILD_MODULE_ApplicationFramework:BOOL="${BUILD_ApplicationFramework}" \
 -DBUILD_MODULE_DataExchange:BOOL="${BUILD_DataExchange}" \
+-DBUILD_MODULE_DETools:BOOL="${BUILD_DETools}" \
 -DBUILD_MODULE_Draw:BOOL="OFF" \
 -DBUILD_DOC_Overview:BOOL="OFF" "${aSrcRoot}"
 
@@ -92,6 +94,7 @@ cmake -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE:FILEPATH="${aToolchain}" \
 -DBUILD_MODULE_Visualization:BOOL="${BUILD_Visualization}" \
 -DBUILD_MODULE_ApplicationFramework:BOOL="${BUILD_ApplicationFramework}" \
 -DBUILD_MODULE_DataExchange:BOOL="${BUILD_DataExchange}" \
+-DBUILD_MODULE_DETools:BOOL="${BUILD_DETools}" \
 -DBUILD_MODULE_Draw:BOOL="OFF" \
 -DBUILD_DOC_Overview:BOOL="OFF" "${aSrcRoot}"
 
diff --git a/adm/scripts/wasm_custom.bat.template b/adm/scripts/wasm_custom.bat.template
index 0c52467a6a..91907c7738 100644
--- a/adm/scripts/wasm_custom.bat.template
+++ b/adm/scripts/wasm_custom.bat.template
@@ -23,6 +23,7 @@ rem set "BUILD_ModelingAlgorithms=ON"
 rem set "BUILD_Visualization=ON"
 rem set "BUILD_ApplicationFramework=ON"
 rem set "BUILD_DataExchange=ON"
+rem set "BUILD_DETools=OFF"
 
 rem set "USE_RAPIDJSON=ON"
 rem set "USE_DRACO=ON"
diff --git a/adm/scripts/wasm_custom.sh.template b/adm/scripts/wasm_custom.sh.template
index 29157c92c7..dd3d6c7fe3 100644
--- a/adm/scripts/wasm_custom.sh.template
+++ b/adm/scripts/wasm_custom.sh.template
@@ -14,3 +14,4 @@ export EMSDK_ROOT="$aSrcRoot/../emsdk"
 #export BUILD_Visualization=ON
 #export BUILD_ApplicationFramework=ON
 #export BUILD_DataExchange=ON
+#export BUILD_DETools=OFF
diff --git a/src/ExpToCasExe/ExpToCasExe.cxx b/src/ExpToCasExe/ExpToCasExe.cxx
index c0b25eeab1..1f0ce0ae56 100644
--- a/src/ExpToCasExe/ExpToCasExe.cxx
+++ b/src/ExpToCasExe/ExpToCasExe.cxx
@@ -281,7 +281,7 @@ static Standard_Boolean LoadList (const char *theFileName,
 // function : main
 // purpose  :
 //=======================================================================
-Standard_Integer main (const Standard_Integer argc, const char* argv[])
+int main (int argc, char* argv[])
 {
   if (argc < 2)
   {
diff --git a/src/FlexLexer/FILES b/src/FlexLexer/FILES
new file mode 100644
index 0000000000..254a004963
--- /dev/null
+++ b/src/FlexLexer/FILES
@@ -0,0 +1 @@
+FlexLexer.h
diff --git a/src/ExpToCasExe/FlexLexer.h b/src/FlexLexer/FlexLexer.h
similarity index 100%
rename from src/ExpToCasExe/FlexLexer.h
rename to src/FlexLexer/FlexLexer.h
diff --git a/src/OS/DataExchange.tcl b/src/OS/DataExchange.tcl
index cbb12e7d56..3f3b5badc7 100644
--- a/src/OS/DataExchange.tcl
+++ b/src/OS/DataExchange.tcl
@@ -18,7 +18,7 @@ proc DataExchange:toolkits { } {
   return [list TKXSBase TKSTEPBase TKSTEPAttr TKSTEP209 TKSTEP TKIGES \
                TKXCAF TKXDEIGES TKXDESTEP \
                TKXDE TKXDECascade \
-               TKSTL TKVRML TKXmlXCAF TKBinXCAF TKRWMesh TKExpress]
+               TKSTL TKVRML TKXmlXCAF TKBinXCAF TKRWMesh]
 }
 
 ;#
@@ -29,7 +29,6 @@ proc DataExchange:ressources { } {
 	    [list both r XSMessage {} ] \
 	    [list both r SHMessage {} ] \
 	    [list both r XSTEPResource {} ] \
-	    [list both x ExpToCasExe {} ] \
 	    ]
 }
 ;#
diff --git a/src/StepFile/FILES b/src/StepFile/FILES
index 733a836129..5c8fa85a09 100755
--- a/src/StepFile/FILES
+++ b/src/StepFile/FILES
@@ -7,4 +7,3 @@ StepFile_Read.cxx
 StepFile_Read.hxx
 step.lex
 step.yacc
-FlexLexer.h
diff --git a/src/StepFile/FlexLexer.h b/src/StepFile/FlexLexer.h
deleted file mode 100644
index c4dad2b142..0000000000
--- a/src/StepFile/FlexLexer.h
+++ /dev/null
@@ -1,220 +0,0 @@
-// -*-C++-*-
-// FlexLexer.h -- define interfaces for lexical analyzer classes generated
-// by flex
-
-// Copyright (c) 1993 The Regents of the University of California.
-// All rights reserved.
-//
-// This code is derived from software contributed to Berkeley by
-// Kent Williams and Tom Epperly.
-//
-//  Redistribution and use in source and binary forms, with or without
-//  modification, are permitted provided that the following conditions
-//  are met:
-
-//  1. Redistributions of source code must retain the above copyright
-//  notice, this list of conditions and the following disclaimer.
-//  2. Redistributions in binary form must reproduce the above copyright
-//  notice, this list of conditions and the following disclaimer in the
-//  documentation and/or other materials provided with the distribution.
-
-//  Neither the name of the University nor the names of its contributors
-//  may be used to endorse or promote products derived from this software
-//  without specific prior written permission.
-
-//  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-//  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-//  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-//  PURPOSE.
-
-// This file defines FlexLexer, an abstract class which specifies the
-// external interface provided to flex C++ lexer objects, and yyFlexLexer,
-// which defines a particular lexer class.
-//
-// If you want to create multiple lexer classes, you use the -P flag
-// to rename each yyFlexLexer to some other xxFlexLexer.  You then
-// include <FlexLexer.h> in your other sources once per lexer class:
-//
-//      #undef yyFlexLexer
-//      #define yyFlexLexer xxFlexLexer
-//      #include <FlexLexer.h>
-//
-//      #undef yyFlexLexer
-//      #define yyFlexLexer zzFlexLexer
-//      #include <FlexLexer.h>
-//      ...
-
-#ifndef __FLEX_LEXER_H
-// Never included before - need to define base class.
-#define __FLEX_LEXER_H
-
-#include <iostream>
-
-extern "C++" {
-
-struct yy_buffer_state;
-typedef int yy_state_type;
-
-class FlexLexer
-{
-public:
-  virtual ~FlexLexer()        { }
-
-  const char* YYText() const  { return yytext; }
-  int YYLeng()        const   { return yyleng; }
-
-  virtual void
-  yy_switch_to_buffer( yy_buffer_state* new_buffer ) = 0;
-  virtual yy_buffer_state* yy_create_buffer( std::istream* s, int size ) = 0;
-  virtual yy_buffer_state* yy_create_buffer( std::istream& s, int size ) = 0;
-  virtual void yy_delete_buffer( yy_buffer_state* b ) = 0;
-  virtual void yyrestart( std::istream* s ) = 0;
-  virtual void yyrestart( std::istream& s ) = 0;
-
-  virtual int yylex() = 0;
-
-  // Call yylex with new input/output sources.
-  int yylex( std::istream& new_in, std::ostream& new_out )
-  {
-    switch_streams( new_in, new_out );
-    return yylex();
-  }
-
-  int yylex( std::istream* new_in, std::ostream* new_out = 0)
-  {
-    switch_streams( new_in, new_out );
-    return yylex();
-  }
-
-  // Switch to new input/output streams.  A nil stream pointer
-  // indicates "keep the current one".
-  virtual void switch_streams( std::istream* new_in,
-                               std::ostream* new_out ) = 0;
-  virtual void switch_streams( std::istream& new_in,
-                               std::ostream& new_out ) = 0;
-
-  int lineno() const          { return yylineno; }
-
-  int debug() const           { return yy_flex_debug; }
-  void set_debug( int flag )  { yy_flex_debug = flag; }
-
-protected:
-  char* yytext;
-  int yyleng;
-  int yylineno;       // only maintained if you use %option yylineno
-  int yy_flex_debug;  // only has effect with -d or "%option debug"
-};
-
-}
-#endif // FLEXLEXER_H
-
-#if defined(yyFlexLexer) || ! defined(yyFlexLexerOnce)
-// Either this is the first time through (yyFlexLexerOnce not defined),
-// or this is a repeated include to define a different flavor of
-// yyFlexLexer, as discussed in the flex manual.
-# define yyFlexLexerOnce
-
-extern "C++" {
-
-class yyFlexLexer : public FlexLexer {
-public:
-  // arg_yyin and arg_yyout default to the cin and cout, but we
-  // only make that assignment when initializing in yylex().
-  yyFlexLexer( std::istream& arg_yyin, std::ostream& arg_yyout );
-  yyFlexLexer( std::istream* arg_yyin = 0, std::ostream* arg_yyout = 0 );
-private:
-  void ctor_common();
-
-public:
-
-  virtual ~yyFlexLexer();
-
-  void yy_switch_to_buffer( yy_buffer_state* new_buffer );
-  yy_buffer_state* yy_create_buffer( std::istream* s, int size );
-  yy_buffer_state* yy_create_buffer( std::istream& s, int size );
-  void yy_delete_buffer( yy_buffer_state* b );
-  void yyrestart( std::istream* s );
-  void yyrestart( std::istream& s );
-
-  void yypush_buffer_state( yy_buffer_state* new_buffer );
-  void yypop_buffer_state();
-
-  virtual int yylex();
-  virtual void switch_streams( std::istream& new_in, std::ostream& new_out );
-  virtual void switch_streams( std::istream* new_in = 0, std::ostream* new_out = 0 );
-  virtual int yywrap();
-
-protected:
-  virtual int LexerInput( char* buf, int max_size );
-  virtual void LexerOutput( const char* buf, int size );
-  virtual void LexerError( const char* msg );
-
-  void yyunput( int c, char* buf_ptr );
-  int yyinput();
-
-  void yy_load_buffer_state();
-  void yy_init_buffer( yy_buffer_state* b, std::istream& s );
-  void yy_flush_buffer( yy_buffer_state* b );
-
-  int yy_start_stack_ptr;
-  int yy_start_stack_depth;
-  int* yy_start_stack;
-
-  void yy_push_state( int new_state );
-  void yy_pop_state();
-  int yy_top_state();
-
-  yy_state_type yy_get_previous_state();
-  yy_state_type yy_try_NUL_trans( yy_state_type current_state );
-  int yy_get_next_buffer();
-
-  std::istream yyin;  // input source for default LexerInput
-  std::ostream yyout; // output sink for default LexerOutput
-
-  // yy_hold_char holds the character lost when yytext is formed.
-  char yy_hold_char;
-
-  // Number of characters read into yy_ch_buf.
-  int yy_n_chars;
-
-  // Points to current character in buffer.
-  char* yy_c_buf_p;
-
-  int yy_init;                // whether we need to initialize
-  int yy_start;               // start state number
-
-  // Flag which is used to allow yywrap()'s to do buffer switches
-  // instead of setting up a fresh yyin.  A bit of a hack ...
-  int yy_did_buffer_switch_on_eof;
-
-
-  size_t yy_buffer_stack_top; /**< index of top of stack. */
-  size_t yy_buffer_stack_max; /**< capacity of stack. */
-  yy_buffer_state ** yy_buffer_stack; /**< Stack as an array. */
-  void yyensure_buffer_stack(void);
-
-  // The following are not always needed, but may be depending
-  // on use of certain flex features (like REJECT or yymore()).
-
-  yy_state_type yy_last_accepting_state;
-  char* yy_last_accepting_cpos;
-
-  yy_state_type* yy_state_buf;
-  yy_state_type* yy_state_ptr;
-
-  char* yy_full_match;
-  int* yy_full_state;
-  int yy_full_lp;
-
-  int yy_lp;
-  int yy_looking_for_trail_begin;
-
-  int yy_more_flag;
-  int yy_more_len;
-  int yy_more_offset;
-  int yy_prev_more_offset;
-};
-
-}
-
-#endif // yyFlexLexer || ! yyFlexLexerOnce
diff --git a/src/TKernel/PACKAGES b/src/TKernel/PACKAGES
index a10bf8d75d..ee92fa32b7 100755
--- a/src/TKernel/PACKAGES
+++ b/src/TKernel/PACKAGES
@@ -14,3 +14,4 @@ UnitsAPI
 UnitsMethods
 NCollection
 Message
+FlexLexer