diff --git a/src/core/expression/qgsexpression_p.h b/src/core/expression/qgsexpression_p.h
deleted file mode 100644
index 26279995f68..00000000000
--- a/src/core/expression/qgsexpression_p.h
+++ /dev/null
@@ -1,111 +0,0 @@
-/***************************************************************************
-     qgsexpression_p.h
-     ---------------
-    Date                 : October 2019
-    Copyright            : (C) 2019 by Matthias Kuhn
-    Email                : matthias@opengis.ch
- ***************************************************************************
- *                                                                         *
- *   This program is free software; you can redistribute it and/or modify  *
- *   it under the terms of the GNU General Public License as published by  *
- *   the Free Software Foundation; either version 2 of the License, or     *
- *   (at your option) any later version.                                   *
- *                                                                         *
- ***************************************************************************/
-#ifndef QGSEXPRESSIONPRIVATE_H
-#define QGSEXPRESSIONPRIVATE_H
-
-/// @cond PRIVATE
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the QGIS API.  It exists purely as an
-// implementation detail. This header file may change from version to
-// version without notice, or even be removed.
-//
-
-#define SIP_NO_FILE
-
-#include "qgsexpression.h"
-
-struct HelpArg
-{
-  HelpArg( const QString &arg, const QString &desc, bool descOnly = false, bool syntaxOnly = false,
-           bool optional = false, const QString &defaultVal = QString() )
-    : mArg( arg )
-    , mDescription( desc )
-    , mDescOnly( descOnly )
-    , mSyntaxOnly( syntaxOnly )
-    , mOptional( optional )
-    , mDefaultVal( defaultVal )
-  {}
-
-  QString mArg;
-  QString mDescription;
-  bool mDescOnly;
-  bool mSyntaxOnly;
-  bool mOptional;
-  QString mDefaultVal;
-};
-
-struct HelpExample
-{
-  HelpExample( const QString &expression, const QString &returns, const QString &note = QString() )
-    : mExpression( expression )
-    , mReturns( returns )
-    , mNote( note )
-  {}
-
-  QString mExpression;
-  QString mReturns;
-  QString mNote;
-};
-
-
-struct HelpVariant
-{
-  HelpVariant( const QString &name, const QString &description,
-               const QList<HelpArg> &arguments = QList<HelpArg>(),
-               bool variableLenArguments = false,
-               const QList<HelpExample> &examples = QList<HelpExample>(),
-               const QString &notes = QString() )
-    : mName( name )
-    , mDescription( description )
-    , mArguments( arguments )
-    , mVariableLenArguments( variableLenArguments )
-    , mExamples( examples )
-    , mNotes( notes )
-  {}
-
-  QString mName;
-  QString mDescription;
-  QList<HelpArg> mArguments;
-  bool mVariableLenArguments;
-  QList<HelpExample> mExamples;
-  QString mNotes;
-};
-
-
-struct Help
-{
-  //! Constructor for expression help
-  Help() = default;
-
-  Help( const QString &name, const QString &type, const QString &description, const QList<HelpVariant> &variants )
-    : mName( name )
-    , mType( type )
-    , mDescription( description )
-    , mVariants( variants )
-  {}
-
-  QString mName;
-  QString mType;
-  QString mDescription;
-  QList<HelpVariant> mVariants;
-};
-
-typedef QHash<QString, Help> HelpTextHash;
-Q_GLOBAL_STATIC( HelpTextHash, sFunctionHelpTexts )
-#endif // QGSEXPRESSIONPRIVATE_H