diff --git a/src/RxFree/build/Legacy/CompositeDisposable.cs b/src/RxFree/build/Legacy/CompositeDisposable.cs
index a6dba6b..6bba72a 100644
--- a/src/RxFree/build/Legacy/CompositeDisposable.cs
+++ b/src/RxFree/build/Legacy/CompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
diff --git a/src/RxFree/build/Legacy/Disposable.cs b/src/RxFree/build/Legacy/Disposable.cs
index 313f7bc..a05001c 100644
--- a/src/RxFree/build/Legacy/Disposable.cs
+++ b/src/RxFree/build/Legacy/Disposable.cs
@@ -1,4 +1,5 @@
-using System.Diagnostics.CodeAnalysis;
+// <auto-generated />
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 
 namespace System
diff --git a/src/RxFree/build/Legacy/ObservableExtensions.cs b/src/RxFree/build/Legacy/ObservableExtensions.cs
index 7233c45..3aba91e 100644
--- a/src/RxFree/build/Legacy/ObservableExtensions.cs
+++ b/src/RxFree/build/Legacy/ObservableExtensions.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
diff --git a/src/RxFree/build/Legacy/StableCompositeDisposable.cs b/src/RxFree/build/Legacy/StableCompositeDisposable.cs
index ac54127..21c2f99 100644
--- a/src/RxFree/build/Legacy/StableCompositeDisposable.cs
+++ b/src/RxFree/build/Legacy/StableCompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.ComponentModel;
+// <auto-generated />
+using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 
 namespace System
diff --git a/src/RxFree/build/Legacy/Subject.cs b/src/RxFree/build/Legacy/Subject.cs
index 42c820a..3f1058b 100644
--- a/src/RxFree/build/Legacy/Subject.cs
+++ b/src/RxFree/build/Legacy/Subject.cs
@@ -1,3 +1,4 @@
+// <auto-generated />
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT License.
 
diff --git a/src/RxFree/build/NotNull/CompositeDisposable.cs b/src/RxFree/build/NotNull/CompositeDisposable.cs
index f99d2f1..7bd13d9 100644
--- a/src/RxFree/build/NotNull/CompositeDisposable.cs
+++ b/src/RxFree/build/NotNull/CompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
diff --git a/src/RxFree/build/NotNull/Disposable.cs b/src/RxFree/build/NotNull/Disposable.cs
index 4cae65d..8f6936c 100644
--- a/src/RxFree/build/NotNull/Disposable.cs
+++ b/src/RxFree/build/NotNull/Disposable.cs
@@ -1,4 +1,5 @@
-using System.Diagnostics.CodeAnalysis;
+// <auto-generated />
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 
 namespace System
diff --git a/src/RxFree/build/NotNull/ObservableExtensions.cs b/src/RxFree/build/NotNull/ObservableExtensions.cs
index 7233c45..3aba91e 100644
--- a/src/RxFree/build/NotNull/ObservableExtensions.cs
+++ b/src/RxFree/build/NotNull/ObservableExtensions.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
diff --git a/src/RxFree/build/NotNull/StableCompositeDisposable.cs b/src/RxFree/build/NotNull/StableCompositeDisposable.cs
index ac54127..21c2f99 100644
--- a/src/RxFree/build/NotNull/StableCompositeDisposable.cs
+++ b/src/RxFree/build/NotNull/StableCompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.ComponentModel;
+// <auto-generated />
+using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 
 namespace System
diff --git a/src/RxFree/build/NotNull/Subject.cs b/src/RxFree/build/NotNull/Subject.cs
index 74ebcb9..3867e6c 100644
--- a/src/RxFree/build/NotNull/Subject.cs
+++ b/src/RxFree/build/NotNull/Subject.cs
@@ -1,3 +1,4 @@
+// <auto-generated />
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT License.
 
diff --git a/src/RxFree/build/Nullable/CompositeDisposable.cs b/src/RxFree/build/Nullable/CompositeDisposable.cs
index f99d2f1..7bd13d9 100644
--- a/src/RxFree/build/Nullable/CompositeDisposable.cs
+++ b/src/RxFree/build/Nullable/CompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
diff --git a/src/RxFree/build/Nullable/Disposable.cs b/src/RxFree/build/Nullable/Disposable.cs
index 4cae65d..8f6936c 100644
--- a/src/RxFree/build/Nullable/Disposable.cs
+++ b/src/RxFree/build/Nullable/Disposable.cs
@@ -1,4 +1,5 @@
-using System.Diagnostics.CodeAnalysis;
+// <auto-generated />
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 
 namespace System
diff --git a/src/RxFree/build/Nullable/ObservableExtensions.cs b/src/RxFree/build/Nullable/ObservableExtensions.cs
index 7233c45..3aba91e 100644
--- a/src/RxFree/build/Nullable/ObservableExtensions.cs
+++ b/src/RxFree/build/Nullable/ObservableExtensions.cs
@@ -1,4 +1,5 @@
-using System.CodeDom.Compiler;
+// <auto-generated />
+using System.CodeDom.Compiler;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
diff --git a/src/RxFree/build/Nullable/StableCompositeDisposable.cs b/src/RxFree/build/Nullable/StableCompositeDisposable.cs
index ac54127..21c2f99 100644
--- a/src/RxFree/build/Nullable/StableCompositeDisposable.cs
+++ b/src/RxFree/build/Nullable/StableCompositeDisposable.cs
@@ -1,4 +1,5 @@
-using System.ComponentModel;
+// <auto-generated />
+using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 
 namespace System
diff --git a/src/RxFree/build/Nullable/Subject.cs b/src/RxFree/build/Nullable/Subject.cs
index 30492ef..5727999 100644
--- a/src/RxFree/build/Nullable/Subject.cs
+++ b/src/RxFree/build/Nullable/Subject.cs
@@ -1,3 +1,4 @@
+// <auto-generated />
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT License.