/usr/include/caf/io/ is in libcaf-dev 0.13.2-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/caf/io/accept_handle.hpp
/usr/include/caf/io/all.hpp
/usr/include/caf/io/asio_network.hpp
/usr/include/caf/io/basp.hpp
/usr/include/caf/io/basp_broker.hpp
/usr/include/caf/io/broker.hpp
/usr/include/caf/io/connection_handle.hpp
/usr/include/caf/io/fwd.hpp
/usr/include/caf/io/handle.hpp
/usr/include/caf/io/hook.hpp
/usr/include/caf/io/max_msg_size.hpp
/usr/include/caf/io/middleman.hpp
/usr/include/caf/io/middleman_actor.hpp
/usr/include/caf/io/network/
/usr/include/caf/io/network/acceptor_manager.hpp
/usr/include/caf/io/network/default_multiplexer.hpp
/usr/include/caf/io/network/interfaces.hpp
/usr/include/caf/io/network/manager.hpp
/usr/include/caf/io/network/multiplexer.hpp
/usr/include/caf/io/network/native_socket.hpp
/usr/include/caf/io/network/operation.hpp
/usr/include/caf/io/network/protocol.hpp
/usr/include/caf/io/network/stream_manager.hpp
/usr/include/caf/io/publish.hpp
/usr/include/caf/io/publish_local_groups.hpp
/usr/include/caf/io/receive_policy.hpp
/usr/include/caf/io/remote_actor.hpp
/usr/include/caf/io/remote_group.hpp
/usr/include/caf/io/spawn_io.hpp
/usr/include/caf/io/system_messages.hpp
/usr/include/caf/io/unpublish.hpp