diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 5fe8a5a8e..647022e68 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -17,7 +17,6 @@
 #include "compat.h"
 #include "engine_priv.h"
 #include "palette.h"
-#include "scriptfile.h"
 #include "gamecvars.h"
 #include "c_console.h"
 #include "v_2ddrawer.h"
diff --git a/source/core/def_.cpp b/source/core/def_.cpp
deleted file mode 100644
index 1801b958c..000000000
--- a/source/core/def_.cpp
+++ /dev/null
@@ -1,139 +0,0 @@
-/*
-** def.cpp
-** Rewritten .def parser free of Build license restrictions.
-**
-**---------------------------------------------------------------------------
-** Copyright 2020 Christoph Oelckers
-** All rights reserved.
-**
-** 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.
-** 3. The name of the author may not be used to endorse or promote products
-**    derived from this software without specific prior written permission.
-**
-** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OFf
-** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-**---------------------------------------------------------------------------
-**
-*/  
-
-
-#include "build.h"
-#include "compat.h"
-
-#include "mdsprite.h"  // md3model_t
-#include "buildtiles.h"
-#include "bitmap.h"
-#include "m_argv.h"
-#include "gamecontrol.h"
-#include "palettecontainer.h"
-#include "mapinfo.h"
-#include "sc_man.h"
-
-
-
-
-
-bool ParseDefFile(const char* file, FScanner *parent)
-{
-	int lump = fileSystem.FindFile(file);
-	bool success = false;
-	if (lump == -1)
-	{
-		if (!parent) Printf(PRINT_BOLD, "%sd: file not found\n", file);
-		else parent->ScriptError("%s: file not found\n", file);
-		return false;
-	}
-	FScanner sc;
-	if (parent) sc.symbols = std::move(parent->symbols); // the child parser needs to add to the parent's symbol table so transfer its ownership for the parsing run.
-	sc.OpenLumpNum(lump);
-	sc.SetCMode(true);
-	sc.SetNoOctals(true);
-	sc.SetNoFatalErrors(true);
-	FString str;
-
-	while (sc.GetString())
-	{	
-		if (sc.Compare({"#include", "include"}))
-		{
-			if (!sc.MustGetString())
-				ParseDefFile(sc.String, &sc);
-		}
-		else if (sc.Compare({"#includedefault", "includedefault"}))
-		{
-			ParseDefFile(G_DefaultDefFile(), &sc);
-		}
-		else if (sc.Compare({"#define", "define"}))
-		{
-			parseDefine(sc);
-		}
-		else if (sc.Compare("definetexture"))
-		{
-			parseDefineTexture(sc);
-		}
-		else if (sc.Compare("defineskybox"))
-		{
-            parseDefineSkybox(sc);
-		}
-		else if (sc.Compare("definetint"))
-		{
-            parseDefineTint(sc);
-		}
-		else if (sc.Compare("alphahack")) // why 'hack'?
-		{
-            parseAlphaHack(sc);
-		}
-		else if (sc.Compare("alphahackrange")) // why 'hack'?
-		{
-            parseAlphaHackRange(sc);
-		}
-		if (sc.Compare({"spritecol", "2dcolidxrange"))	// only used by Mapster32 so just read over them and ignore the result
-		{
-            parseDiscard<3>(sc);
-		}
-		else if (sc.Compare("2dcol")) // same here
-		{
-            parseDiscard<4>(sc);
-		}
-		else if (sc.Compare("fogpal"))
-		{
-            parseFogPal(sc);
-		}
-		else if (sc.Compare("nofloorpalrange"))
-		{
-            parseNoFloorpalRange(sc);
-		}
-		else if (sc.Compare("loadgrp"))
-		{
-            parseLoadGrp(sc);
-		}
-		else if (sc.Compare("cachesize") || sc.Compare("shadefactor"))
-		{
-            parseDiscard<1>(sc);
-		}
-		else if (sc.Compare("artfile"))
-		{
-            parseArtFile(sc);
-		}
-
-	}
-	success = true;
-
-	if (parent) parent->symbols = std::move(sc.symbols);
-	return success;
-}
\ No newline at end of file
diff --git a/source/core/defparser.cpp b/source/core/defparser.cpp
index e51e95279..b4ed74373 100644
--- a/source/core/defparser.cpp
+++ b/source/core/defparser.cpp
@@ -1,8 +1,7 @@
 
 /*
-** parsefuncs.h
-** handlers for .def parser
-** only to be included by the actual parser
+** def.cpp
+** Rewritten .def parser free of Build license restrictions.
 **
 **---------------------------------------------------------------------------
 ** Copyright 2021 Christoph Oelckers