V2 but existing endpoint removals are only applied in V2.
    *   Deprecates behavior where device assignment overrides collocation
        constraints inside a collocation context manager.
*   Keras & Python API
    *   Add to Keras functionality analogous to
        `tf.register_tensor_conversion_function`.
    *   Subclassed Keras models can now be saved through

        "//tensorflow/core/profiler/lib:traceme",
        "//tensorflow/core/profiler/rpc/client:profiler_client_impl",
        "//tensorflow/core/profiler/rpc:profiler_server_impl",
        "//tensorflow/core/util:managed_stack_trace",
        "//tensorflow/core:all_kernels",
        "//tensorflow/core:core_cpu",
        "//tensorflow/core:direct_session",
        "//tensorflow/core:framework_internal",

    // instead allow ForwardAccumulator some control over the current tape set
    // (so it can deactivate itself and activate its GradientTape). Currently
    // that is managed by the language binding and would require relatively
    // messy callbacks.
    call_state_.top().backward_tape->RecordOperation(
        op_type, output_tensors, input_tensor_id, input_dtypes,