diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 809f5131b4..8a8713f194 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 name: CI
 
diff --git a/lib/elixir/lib/module/types/apply.ex b/lib/elixir/lib/module/types/apply.ex
index 147189fa36..c9aac74109 100644
--- a/lib/elixir/lib/module/types/apply.ex
+++ b/lib/elixir/lib/module/types/apply.ex
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 defmodule Module.Types.Apply do
   # Typing functionality shared between Expr and Pattern.
diff --git a/lib/elixir/lib/module/types/of.ex b/lib/elixir/lib/module/types/of.ex
index be8d23e2d1..cb8c28e817 100644
--- a/lib/elixir/lib/module/types/of.ex
+++ b/lib/elixir/lib/module/types/of.ex
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 defmodule Module.Types.Of do
   # Typing functionality shared between Expr and Pattern.
diff --git a/lib/elixir/scripts/diff.exs b/lib/elixir/scripts/diff.exs
index 06a20bef31..5a12794a34 100644
--- a/lib/elixir/scripts/diff.exs
+++ b/lib/elixir/scripts/diff.exs
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 defmodule Diff do
   @moduledoc """
diff --git a/lib/elixir/test/elixir/calendar_test.exs b/lib/elixir/test/elixir/calendar_test.exs
index 54291ce3d1..c812f311ac 100644
--- a/lib/elixir/test/elixir/calendar_test.exs
+++ b/lib/elixir/test/elixir/calendar_test.exs
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 Code.require_file("test_helper.exs", __DIR__)
 
diff --git a/lib/elixir/test/elixir/module/types/type_helper.exs b/lib/elixir/test/elixir/module/types/type_helper.exs
index 857af24d9a..79c4997ebf 100644
--- a/lib/elixir/test/elixir/module/types/type_helper.exs
+++ b/lib/elixir/test/elixir/module/types/type_helper.exs
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 Code.require_file("../../test_helper.exs", __DIR__)
 
diff --git a/lib/mix/lib/mix/tasks/app.config.ex b/lib/mix/lib/mix/tasks/app.config.ex
index 95334d7278..cc40225871 100644
--- a/lib/mix/lib/mix/tasks/app.config.ex
+++ b/lib/mix/lib/mix/tasks/app.config.ex
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 defmodule Mix.Tasks.App.Config do
   use Mix.Task
diff --git a/lib/mix/lib/mix/tasks/test.coverage.ex b/lib/mix/lib/mix/tasks/test.coverage.ex
index c85c89adda..ed3579be3f 100644
--- a/lib/mix/lib/mix/tasks/test.coverage.ex
+++ b/lib/mix/lib/mix/tasks/test.coverage.ex
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 defmodule Mix.Tasks.Test.Coverage do
   use Mix.Task
diff --git a/lib/mix/test/mix/tasks/app.config_test.exs b/lib/mix/test/mix/tasks/app.config_test.exs
index b32a71b282..13b1944cc8 100644
--- a/lib/mix/test/mix/tasks/app.config_test.exs
+++ b/lib/mix/test/mix/tasks/app.config_test.exs
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2021 The Elixir Team
+# SPDX-FileCopyrightText: 2012 Plataformatec
 
 Code.require_file("../../test_helper.exs", __DIR__)