diff --git a/CMakeLists.txt b/CMakeLists.txt
index fd6a02ac0..dabfb1480 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -106,7 +106,6 @@ set(PYBIND11_HEADERS
     include/pybind11/detail/init.h
     include/pybind11/detail/internals.h
     include/pybind11/detail/smart_holder_poc.h
-    include/pybind11/detail/smart_holder_type_casters.h
     include/pybind11/detail/typeid.h
     include/pybind11/attr.h
     include/pybind11/buffer_info.h
diff --git a/tests/extra_python_package/test_files.py b/tests/extra_python_package/test_files.py
index 5bdd22091..4971d52a8 100644
--- a/tests/extra_python_package/test_files.py
+++ b/tests/extra_python_package/test_files.py
@@ -43,7 +43,6 @@ detail_headers = {
     "include/pybind11/detail/init.h",
     "include/pybind11/detail/internals.h",
     "include/pybind11/detail/smart_holder_poc.h",
-    "include/pybind11/detail/smart_holder_type_casters.h",
     "include/pybind11/detail/typeid.h",
 }