/usr/include/grpc/ is in libgrpc-dev 1.3.2-1.1~build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/grpc/byte_buffer.h
/usr/include/grpc/byte_buffer_reader.h
/usr/include/grpc/census.h
/usr/include/grpc/compression.h
/usr/include/grpc/grpc.h
/usr/include/grpc/grpc_cronet.h
/usr/include/grpc/grpc_posix.h
/usr/include/grpc/grpc_security.h
/usr/include/grpc/grpc_security_constants.h
/usr/include/grpc/impl/
/usr/include/grpc/impl/codegen/
/usr/include/grpc/impl/codegen/atm.h
/usr/include/grpc/impl/codegen/atm_gcc_atomic.h
/usr/include/grpc/impl/codegen/atm_gcc_sync.h
/usr/include/grpc/impl/codegen/atm_windows.h
/usr/include/grpc/impl/codegen/byte_buffer_reader.h
/usr/include/grpc/impl/codegen/compression_types.h
/usr/include/grpc/impl/codegen/connectivity_state.h
/usr/include/grpc/impl/codegen/exec_ctx_fwd.h
/usr/include/grpc/impl/codegen/gpr_slice.h
/usr/include/grpc/impl/codegen/gpr_types.h
/usr/include/grpc/impl/codegen/grpc_types.h
/usr/include/grpc/impl/codegen/port_platform.h
/usr/include/grpc/impl/codegen/propagation_bits.h
/usr/include/grpc/impl/codegen/slice.h
/usr/include/grpc/impl/codegen/status.h
/usr/include/grpc/impl/codegen/sync.h
/usr/include/grpc/impl/codegen/sync_generic.h
/usr/include/grpc/impl/codegen/sync_posix.h
/usr/include/grpc/impl/codegen/sync_windows.h
/usr/include/grpc/load_reporting.h
/usr/include/grpc/slice.h
/usr/include/grpc/slice_buffer.h
/usr/include/grpc/status.h
/usr/include/grpc/support/
/usr/include/grpc/support/alloc.h
/usr/include/grpc/support/atm.h
/usr/include/grpc/support/atm_gcc_atomic.h
/usr/include/grpc/support/atm_gcc_sync.h
/usr/include/grpc/support/atm_windows.h
/usr/include/grpc/support/avl.h
/usr/include/grpc/support/cmdline.h
/usr/include/grpc/support/cpu.h
/usr/include/grpc/support/histogram.h
/usr/include/grpc/support/host_port.h
/usr/include/grpc/support/log.h
/usr/include/grpc/support/log_windows.h
/usr/include/grpc/support/port_platform.h
/usr/include/grpc/support/string_util.h
/usr/include/grpc/support/subprocess.h
/usr/include/grpc/support/sync.h
/usr/include/grpc/support/sync_generic.h
/usr/include/grpc/support/sync_posix.h
/usr/include/grpc/support/sync_windows.h
/usr/include/grpc/support/thd.h
/usr/include/grpc/support/time.h
/usr/include/grpc/support/tls.h
/usr/include/grpc/support/tls_gcc.h
/usr/include/grpc/support/tls_msvc.h
/usr/include/grpc/support/tls_pthread.h
/usr/include/grpc/support/useful.h