/usr/include/tbb/internal/ is in libtbb-dev 4.4~20151115-0ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/tbb/internal/_aggregator_impl.h
/usr/include/tbb/internal/_concurrent_queue_impl.h
/usr/include/tbb/internal/_concurrent_unordered_impl.h
/usr/include/tbb/internal/_flow_graph_impl.h
/usr/include/tbb/internal/_flow_graph_indexer_impl.h
/usr/include/tbb/internal/_flow_graph_item_buffer_impl.h
/usr/include/tbb/internal/_flow_graph_join_impl.h
/usr/include/tbb/internal/_flow_graph_node_impl.h
/usr/include/tbb/internal/_flow_graph_tagged_buffer_impl.h
/usr/include/tbb/internal/_flow_graph_trace_impl.h
/usr/include/tbb/internal/_flow_graph_types_impl.h
/usr/include/tbb/internal/_mutex_padding.h
/usr/include/tbb/internal/_range_iterator.h
/usr/include/tbb/internal/_tbb_hash_compare_impl.h
/usr/include/tbb/internal/_tbb_strings.h
/usr/include/tbb/internal/_tbb_windef.h
/usr/include/tbb/internal/_template_helpers.h
/usr/include/tbb/internal/_x86_eliding_mutex_impl.h
/usr/include/tbb/internal/_x86_rtm_rw_mutex_impl.h