diff --git a/platform/platform-impl/src/com/intellij/jdkEx/DisplayModeEx.java b/platform/platform-impl/src/com/intellij/jdkEx/DisplayModeEx.java
index 395c50382304..dd5127feae30 100644
--- a/platform/platform-impl/src/com/intellij/jdkEx/DisplayModeEx.java
+++ b/platform/platform-impl/src/com/intellij/jdkEx/DisplayModeEx.java
@@ -7,7 +7,9 @@ import org.jetbrains.annotations.NotNull;
 
 import java.awt.*;
 
-@ApiStatus.Experimental
+/**
+ * WARNING: For internal usage only.
+ */
 public interface DisplayModeEx {
   boolean isDefault(@NotNull DisplayMode dm);
 }
diff --git a/platform/platform-impl/src/com/intellij/jdkEx/JdkEx.java b/platform/platform-impl/src/com/intellij/jdkEx/JdkEx.java
index df30bf9e3080..182d9cab2733 100644
--- a/platform/platform-impl/src/com/intellij/jdkEx/JdkEx.java
+++ b/platform/platform-impl/src/com/intellij/jdkEx/JdkEx.java
@@ -19,9 +19,10 @@ import java.util.List;
  * Provides extensions for OpenJDK API, implemented in JetBrains JDK.
  * For OpenJDK defaults to some meaningful results where applicable or otherwise throws runtime exception.
  *
+ * WARNING: For internal usage only.
+ *
  * @author tav
  */
-@ApiStatus.Experimental
 public final class JdkEx {
   @SuppressWarnings("unused")
   @NotNull