diff --git a/sycl/include/sycl/backend.hpp b/sycl/include/sycl/backend.hpp
index 6010804c0ec00..a79825eb10e86 100644
--- a/sycl/include/sycl/backend.hpp
+++ b/sycl/include/sycl/backend.hpp
@@ -25,7 +25,6 @@
 #include <sycl/feature_test.hpp>              // for SYCL_BACKEND_OP...
 #include <sycl/image.hpp>                     // for image, image_al...
 #include <sycl/kernel.hpp>                    // for kernel, get_native
-#include <sycl/kernel_bundle.hpp>
 #include <sycl/kernel_bundle_enums.hpp> // for bundle_state
 #include <sycl/platform.hpp>            // for platform, get_n...
 #include <sycl/property_list.hpp>       // for property_list
@@ -46,7 +45,7 @@
 #include <sycl/detail/backend_traits_hip.hpp>
 #endif
 #if SYCL_EXT_ONEAPI_BACKEND_LEVEL_ZERO
-#include <sycl/detail/backend_traits_level_zero.hpp> // for _ze_command_lis...
+// #include <sycl/detail/backend_traits_level_zero.hpp> // for _ze_command_lis...
 #endif
 
 #include <sycl/detail/ur.hpp>
@@ -59,6 +58,9 @@
 namespace sycl {
 inline namespace _V1 {
 
+template<bundle_state State>
+class kernel_bundle;
+
 namespace detail {
 // TODO each backend can have its own custom errc enumeration
 // but the details for this are not fully specified yet
@@ -150,6 +152,7 @@ auto get_native(const queue &Obj) -> backend_return_t<BackendName, queue> {
   int32_t IsImmCmdList;
   ur_native_handle_t Handle = Obj.getNative(IsImmCmdList);
   backend_return_t<BackendName, queue> RetVal;
+#if 0 && SYCL_EXT_ONEAPI_BACKEND_LEVEL_ZERO
   if constexpr (BackendName == backend::ext_oneapi_level_zero)
     RetVal = IsImmCmdList
                  ? backend_return_t<BackendName, queue>{reinterpret_cast<
@@ -157,6 +160,7 @@ auto get_native(const queue &Obj) -> backend_return_t<BackendName, queue> {
                  : backend_return_t<BackendName, queue>{
                        reinterpret_cast<ze_command_queue_handle_t>(Handle)};
   else
+#endif
     RetVal = reinterpret_cast<backend_return_t<BackendName, queue>>(Handle);
 
   return RetVal;
diff --git a/sycl/include/sycl/ext/oneapi/get_kernel_info.hpp b/sycl/include/sycl/ext/oneapi/get_kernel_info.hpp
index bd435426dfcd1..77892020f25eb 100644
--- a/sycl/include/sycl/ext/oneapi/get_kernel_info.hpp
+++ b/sycl/include/sycl/ext/oneapi/get_kernel_info.hpp
@@ -11,10 +11,21 @@
 #include <sycl/detail/export.hpp>
 #include <sycl/detail/info_desc_helpers.hpp>
 #include <sycl/device.hpp>
+#include <sycl/kernel_bundle_enums.hpp>
 #include <sycl/queue.hpp>
 
+#include <vector>
+
 namespace sycl {
 inline namespace _V1 {
+
+template<bundle_state State>
+class kernel_bundle;
+
+template <typename KernelName, bundle_state State>
+kernel_bundle<State> get_kernel_bundle(const context &,
+                                       const std::vector<device> &);
+
 namespace ext::oneapi {
 
 template <typename KernelName, typename Param>
diff --git a/sycl/include/sycl/ext/oneapi/owner_less.hpp b/sycl/include/sycl/ext/oneapi/owner_less.hpp
index 8ece12202f973..53b704426be4f 100644
--- a/sycl/include/sycl/ext/oneapi/owner_less.hpp
+++ b/sycl/include/sycl/ext/oneapi/owner_less.hpp
@@ -29,6 +29,8 @@ namespace ext::oneapi {
 class kernel_id;
 template<bundle_state State>
 class kernel_bundle;
+template<bundle_state State>
+class device_image;
 
 namespace detail {
 template <typename SyclObject> struct owner_less_base {
diff --git a/sycl/include/sycl/handler.hpp b/sycl/include/sycl/handler.hpp
index 164621d310635..0d7d9c5babe36 100644
--- a/sycl/include/sycl/handler.hpp
+++ b/sycl/include/sycl/handler.hpp
@@ -43,7 +43,6 @@
 #include <sycl/id.hpp>
 #include <sycl/item.hpp>
 #include <sycl/kernel.hpp>
-#include <sycl/kernel_bundle.hpp>
 #include <sycl/kernel_bundle_enums.hpp>
 #include <sycl/kernel_handler.hpp>
 #include <sycl/nd_item.hpp>
@@ -1730,36 +1729,18 @@ class __SYCL_EXPORT handler {
   handler &operator=(const handler &) = delete;
   handler &operator=(handler &&) = delete;
 
+  // This is somewhat radical, but to make handler.hpp independtent from
+  // kernel_bundle.hpp, we define those methods within kernel_bundle.hpp
+  // header. Independence is needed in context of potential upcoming split of
+  // sycl.hpp so that users could do fine-grained include's, saving on
+  // compilation time by avoiding using headers for features they don't use.
   template <auto &SpecName>
   void set_specialization_constant(
-      typename std::remove_reference_t<decltype(SpecName)>::value_type Value) {
-
-    setStateSpecConstSet();
-
-    std::shared_ptr<detail::kernel_bundle_impl> KernelBundleImplPtr =
-        getOrInsertHandlerKernelBundle(/*Insert=*/true);
-
-    detail::createSyclObjFromImpl<kernel_bundle<bundle_state::input>>(
-        KernelBundleImplPtr)
-        .set_specialization_constant<SpecName>(Value);
-  }
+      typename std::remove_reference_t<decltype(SpecName)>::value_type Value);
 
   template <auto &SpecName>
   typename std::remove_reference_t<decltype(SpecName)>::value_type
-  get_specialization_constant() const {
-
-    if (isStateExplicitKernelBundle())
-      throw sycl::exception(make_error_code(errc::invalid),
-                            "Specialization constants cannot be read after "
-                            "explicitly setting the used kernel bundle");
-
-    std::shared_ptr<detail::kernel_bundle_impl> KernelBundleImplPtr =
-        getOrInsertHandlerKernelBundle(/*Insert=*/true);
-
-    return detail::createSyclObjFromImpl<kernel_bundle<bundle_state::input>>(
-               KernelBundleImplPtr)
-        .get_specialization_constant<SpecName>();
-  }
+  get_specialization_constant() const;
 
   void
   use_kernel_bundle(const kernel_bundle<bundle_state::executable> &ExecBundle);
diff --git a/sycl/include/sycl/kernel_bundle.hpp b/sycl/include/sycl/kernel_bundle.hpp
index 1237bc0651b40..d279b2924c8e7 100644
--- a/sycl/include/sycl/kernel_bundle.hpp
+++ b/sycl/include/sycl/kernel_bundle.hpp
@@ -14,8 +14,9 @@
 #include <sycl/detail/kernel_desc.hpp>     // for get_spec_constant_symboli...
 #include <sycl/detail/owner_less_base.hpp> // for OwnerLessBase
 #include <sycl/detail/string_view.hpp>
-#include <sycl/detail/ur.hpp>           // for cast
-#include <sycl/device.hpp>              // for device
+#include <sycl/detail/ur.hpp> // for cast
+#include <sycl/device.hpp>    // for device
+#include <sycl/handler.hpp>
 #include <sycl/kernel.hpp>              // for kernel, kernel_bundle
 #include <sycl/kernel_bundle_enums.hpp> // for bundle_state
 #include <sycl/property_list.hpp>       // for property_list
@@ -1135,6 +1136,37 @@ build(kernel_bundle<bundle_state::ext_oneapi_source> &SourceKB,
 
 } // namespace ext::oneapi::experimental
 
+template <auto &SpecName>
+void handler::set_specialization_constant(
+    typename std::remove_reference_t<decltype(SpecName)>::value_type Value) {
+
+  setStateSpecConstSet();
+
+  std::shared_ptr<detail::kernel_bundle_impl> KernelBundleImplPtr =
+      getOrInsertHandlerKernelBundle(/*Insert=*/true);
+
+  detail::createSyclObjFromImpl<kernel_bundle<bundle_state::input>>(
+      KernelBundleImplPtr)
+      .set_specialization_constant<SpecName>(Value);
+}
+
+template <auto &SpecName>
+typename std::remove_reference_t<decltype(SpecName)>::value_type
+handler::get_specialization_constant() const {
+
+  if (isStateExplicitKernelBundle())
+    throw sycl::exception(make_error_code(errc::invalid),
+                          "Specialization constants cannot be read after "
+                          "explicitly setting the used kernel bundle");
+
+  std::shared_ptr<detail::kernel_bundle_impl> KernelBundleImplPtr =
+      getOrInsertHandlerKernelBundle(/*Insert=*/true);
+
+  return detail::createSyclObjFromImpl<kernel_bundle<bundle_state::input>>(
+             KernelBundleImplPtr)
+      .get_specialization_constant<SpecName>();
+}
+
 } // namespace _V1
 } // namespace sycl
 
diff --git a/sycl/source/detail/handler_proxy.cpp b/sycl/source/detail/handler_proxy.cpp
index 1be993d734062..05ea058cc5d3b 100644
--- a/sycl/source/detail/handler_proxy.cpp
+++ b/sycl/source/detail/handler_proxy.cpp
@@ -8,8 +8,6 @@
 
 #include <sycl/detail/handler_proxy.hpp>
 
-// FIXME: that's a hack
-#include <sycl/kernel_bundle.hpp>
 #include <sycl/handler.hpp>
 
 namespace sycl {
diff --git a/sycl/test/include_deps/sycl_detail_core.hpp.cpp b/sycl/test/include_deps/sycl_detail_core.hpp.cpp
index e9555d3ad95d1..3c813fafe2f61 100644
--- a/sycl/test/include_deps/sycl_detail_core.hpp.cpp
+++ b/sycl/test/include_deps/sycl_detail_core.hpp.cpp
@@ -159,8 +159,6 @@
 // CHECK-NEXT: ext/oneapi/experimental/virtual_functions.hpp
 // CHECK-NEXT: ext/oneapi/kernel_properties/properties.hpp
 // CHECK-NEXT: kernel.hpp
-// CHECK-NEXT: kernel_bundle.hpp
-// CHECK-NEXT: ext/oneapi/experimental/free_function_traits.hpp
 // CHECK-NEXT: sampler.hpp
 // CHECK-NEXT: feature_test.hpp
 // CHECK-EMPTY:
diff --git a/sycl/test/self-contained-handler-hpp.cpp b/sycl/test/self-contained-handler-hpp.cpp
new file mode 100644
index 0000000000000..e71a02104b019
--- /dev/null
+++ b/sycl/test/self-contained-handler-hpp.cpp
@@ -0,0 +1,17 @@
+// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// expected-no-diagnostics
+//
+// The purpose of this test is to ensure that the header containing
+// sycl::handler class definition is self-contained, i.e. we can use handler
+// and no extra headers are needed.
+//
+// TODO: the test should be expanded to use various methods of the class. Due
+// to their template nature we may not test all code paths until we trigger
+// instantiation of a corresponding method.
+// TODO: methods related to specialization constants were moved into
+// kernel_bundle.hpp and therefore handler.hpp is known *not* to be
+// self-contained.
+
+#include <sycl/handler.hpp>
+
+void foo(sycl::handler &h) {}