diff --git a/src/internalwindow.cpp b/src/internalwindow.cpp
index 5ba98ff60a..c7d811d364 100644
--- a/src/internalwindow.cpp
+++ b/src/internalwindow.cpp
@@ -384,9 +384,19 @@ void InternalWindow::popupDone()
     m_handle->hide();
 }
 
+const std::shared_ptr<QOpenGLFramebufferObject> &InternalWindow::fbo() const
+{
+    return m_fbo;
+}
+
+QImage InternalWindow::image() const
+{
+    return m_image;
+}
+
 void InternalWindow::present(const std::shared_ptr<QOpenGLFramebufferObject> fbo)
 {
-    Q_ASSERT(m_internalImage.isNull());
+    Q_ASSERT(m_image.isNull());
 
     const QSizeF bufferSize = fbo->size() / bufferScale();
     QRectF geometry(pos(), clientSizeToFrameSize(bufferSize));
@@ -397,7 +407,7 @@ void InternalWindow::present(const std::shared_ptr<QOpenGLFramebufferObject> fbo
     commitGeometry(geometry);
     markAsMapped();
 
-    m_internalFBO = fbo;
+    m_fbo = fbo;
 
     setDepth(32);
     surfaceItem()->addDamage(surfaceItem()->rect().toAlignedRect());
@@ -405,7 +415,7 @@ void InternalWindow::present(const std::shared_ptr<QOpenGLFramebufferObject> fbo
 
 void InternalWindow::present(const QImage &image, const QRegion &damage)
 {
-    Q_ASSERT(m_internalFBO == nullptr);
+    Q_ASSERT(m_fbo == nullptr);
 
     const QSize bufferSize = image.size() / bufferScale();
     QRectF geometry(pos(), clientSizeToFrameSize(bufferSize));
@@ -416,7 +426,7 @@ void InternalWindow::present(const QImage &image, const QRegion &damage)
     commitGeometry(geometry);
     markAsMapped();
 
-    m_internalImage = image;
+    m_image = image;
 
     setDepth(32);
     surfaceItem()->addDamage(damage);
diff --git a/src/internalwindow.h b/src/internalwindow.h
index b7e647f2af..a09330f514 100644
--- a/src/internalwindow.h
+++ b/src/internalwindow.h
@@ -11,6 +11,8 @@
 
 #include "window.h"
 
+class QOpenGLFramebufferObject;
+
 namespace KWin
 {
 
@@ -61,6 +63,9 @@ public:
     void pointerEnterEvent(const QPointF &globalPos) override;
     void pointerLeaveEvent() override;
 
+    const std::shared_ptr<QOpenGLFramebufferObject> &fbo() const;
+    QImage image() const;
+
     void present(const std::shared_ptr<QOpenGLFramebufferObject> fbo);
     void present(const QImage &image, const QRegion &damage);
     qreal bufferScale() const;
@@ -91,6 +96,8 @@ private:
     NET::WindowType m_windowType = NET::Normal;
     Qt::WindowFlags m_internalWindowFlags = Qt::WindowFlags();
     bool m_userNoBorder = false;
+    std::shared_ptr<QOpenGLFramebufferObject> m_fbo;
+    QImage m_image;
 
     Q_DISABLE_COPY(InternalWindow)
 };
diff --git a/src/scene/surfaceitem_internal.cpp b/src/scene/surfaceitem_internal.cpp
index a08f57a8ed..cfb42382a6 100644
--- a/src/scene/surfaceitem_internal.cpp
+++ b/src/scene/surfaceitem_internal.cpp
@@ -29,7 +29,7 @@ SurfaceItemInternal::SurfaceItemInternal(InternalWindow *window, Scene *scene, I
     setSurfaceToBufferMatrix(surfaceToBufferMatrix);
 }
 
-Window *SurfaceItemInternal::window() const
+InternalWindow *SurfaceItemInternal::window() const
 {
     return m_window;
 }
@@ -75,14 +75,14 @@ void SurfacePixmapInternal::create()
 
 void SurfacePixmapInternal::update()
 {
-    const Window *window = m_item->window();
+    const InternalWindow *window = m_item->window();
 
-    if (window->internalFramebufferObject()) {
-        m_fbo = window->internalFramebufferObject();
+    if (window->fbo()) {
+        m_fbo = window->fbo();
         m_size = m_fbo->size();
         m_hasAlphaChannel = true;
-    } else if (!window->internalImageObject().isNull()) {
-        m_rasterBuffer = window->internalImageObject();
+    } else if (!window->image().isNull()) {
+        m_rasterBuffer = window->image();
         m_size = m_rasterBuffer.size();
         m_hasAlphaChannel = m_rasterBuffer.hasAlphaChannel();
     }
diff --git a/src/scene/surfaceitem_internal.h b/src/scene/surfaceitem_internal.h
index c1d5141af7..0fc1db8499 100644
--- a/src/scene/surfaceitem_internal.h
+++ b/src/scene/surfaceitem_internal.h
@@ -25,7 +25,7 @@ class KWIN_EXPORT SurfaceItemInternal : public SurfaceItem
 public:
     explicit SurfaceItemInternal(InternalWindow *window, Scene *scene, Item *parent = nullptr);
 
-    Window *window() const;
+    InternalWindow *window() const;
 
     QVector<QRectF> shape() const override;
 
@@ -36,7 +36,7 @@ protected:
     std::unique_ptr<SurfacePixmap> createPixmap() override;
 
 private:
-    Window *m_window;
+    InternalWindow *m_window;
 };
 
 class KWIN_EXPORT SurfacePixmapInternal final : public SurfacePixmap
diff --git a/src/window.h b/src/window.h
index f74d8306be..5fa6ba1516 100644
--- a/src/window.h
+++ b/src/window.h
@@ -31,7 +31,6 @@
 #include <QUuid>
 
 class QMouseEvent;
-class QOpenGLFramebufferObject;
 
 namespace KWaylandServer
 {
@@ -741,9 +740,6 @@ public:
     KWaylandServer::SurfaceInterface *surface() const;
     void setSurface(KWaylandServer::SurfaceInterface *surface);
 
-    const std::shared_ptr<QOpenGLFramebufferObject> &internalFramebufferObject() const;
-    QImage internalImageObject() const;
-
     /**
      * @returns Transformation to map from global to window coordinates.
      *
@@ -1541,11 +1537,6 @@ protected:
     int bit_depth;
     NETWinInfo *info;
     bool ready_for_painting;
-    /**
-     * An FBO object KWin internal windows might render to.
-     */
-    std::shared_ptr<QOpenGLFramebufferObject> m_internalFBO;
-    QImage m_internalImage;
 
 protected:
     Window();
@@ -2243,16 +2234,6 @@ inline quint32 Window::pendingSurfaceId() const
     return m_pendingSurfaceId;
 }
 
-inline const std::shared_ptr<QOpenGLFramebufferObject> &Window::internalFramebufferObject() const
-{
-    return m_internalFBO;
-}
-
-inline QImage Window::internalImageObject() const
-{
-    return m_internalImage;
-}
-
 template<class T, class U>
 inline T *Window::findInList(const QList<T *> &list, std::function<bool(const U *)> func)
 {