diff --git a/src/network/access/http2/http2frames_p.h b/src/network/access/http2/http2frames_p.h
index 860555c180..6abed315ca 100644
--- a/src/network/access/http2/http2frames_p.h
+++ b/src/network/access/http2/http2frames_p.h
@@ -40,6 +40,17 @@
 #ifndef HTTP2FRAMES_P_H
 #define HTTP2FRAMES_P_H
 
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of the Network Access API.  This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
 #include "http2protocol_p.h"
 #include "hpack_p.h"
 
diff --git a/src/network/access/http2/http2protocol_p.h b/src/network/access/http2/http2protocol_p.h
index c7088e2179..5c46949e23 100644
--- a/src/network/access/http2/http2protocol_p.h
+++ b/src/network/access/http2/http2protocol_p.h
@@ -40,6 +40,17 @@
 #ifndef HTTP2PROTOCOL_P_H
 #define HTTP2PROTOCOL_P_H
 
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of the Network Access API.  This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
 #include <QtNetwork/qnetworkreply.h>
 #include <QtCore/qloggingcategory.h>
 #include <QtCore/qglobal.h>
diff --git a/src/network/access/http2/http2streams_p.h b/src/network/access/http2/http2streams_p.h
index 7db5d21694..5d9a6ab512 100644
--- a/src/network/access/http2/http2streams_p.h
+++ b/src/network/access/http2/http2streams_p.h
@@ -40,6 +40,17 @@
 #ifndef HTTP2STREAMS_P_H
 #define HTTP2STREAMS_P_H
 
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of the Network Access API.  This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
 #include <private/qhttpnetworkconnectionchannel_p.h>
 #include <private/qhttpnetworkrequest_p.h>
 
diff --git a/src/network/access/qhttp2protocolhandler_p.h b/src/network/access/qhttp2protocolhandler_p.h
index b9658982c0..b146e37dd3 100644
--- a/src/network/access/qhttp2protocolhandler_p.h
+++ b/src/network/access/qhttp2protocolhandler_p.h
@@ -40,6 +40,17 @@
 #ifndef QHTTP2PROTOCOLHANDLER_P_H
 #define QHTTP2PROTOCOLHANDLER_P_H
 
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of the Network Access API.  This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
 #include <private/qhttpnetworkconnectionchannel_p.h>
 #include <private/qabstractprotocolhandler_p.h>
 #include <private/qhttpnetworkrequest_p.h>