/usr/include/ncbi/connect/ is in libncbi6-dev 6.1.20120620-8.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ncbi/connect/connect_export.h
/usr/include/ncbi/connect/ncbi_ansi_ext.h
/usr/include/ncbi/connect/ncbi_assert.h
/usr/include/ncbi/connect/ncbi_base64.h
/usr/include/ncbi/connect/ncbi_buffer.h
/usr/include/ncbi/connect/ncbi_comm.h
/usr/include/ncbi/connect/ncbi_config.h
/usr/include/ncbi/connect/ncbi_connection.h
/usr/include/ncbi/connect/ncbi_connector.h
/usr/include/ncbi/connect/ncbi_connssl.h
/usr/include/ncbi/connect/ncbi_connutil.h
/usr/include/ncbi/connect/ncbi_core.h
/usr/include/ncbi/connect/ncbi_core_c.h
/usr/include/ncbi/connect/ncbi_dispd.h
/usr/include/ncbi/connect/ncbi_file_connector.h
/usr/include/ncbi/connect/ncbi_ftp_connector.h
/usr/include/ncbi/connect/ncbi_gnutls.h
/usr/include/ncbi/connect/ncbi_heapmgr.h
/usr/include/ncbi/connect/ncbi_host_info.h
/usr/include/ncbi/connect/ncbi_host_infop.h
/usr/include/ncbi/connect/ncbi_http_connector.h
/usr/include/ncbi/connect/ncbi_lb.h
/usr/include/ncbi/connect/ncbi_lbsmd.h
/usr/include/ncbi/connect/ncbi_local.h
/usr/include/ncbi/connect/ncbi_memory_connector.h
/usr/include/ncbi/connect/ncbi_priv.h
/usr/include/ncbi/connect/ncbi_sendmail.h
/usr/include/ncbi/connect/ncbi_server_info.h
/usr/include/ncbi/connect/ncbi_server_infop.h
/usr/include/ncbi/connect/ncbi_service.h
/usr/include/ncbi/connect/ncbi_service_connector.h
/usr/include/ncbi/connect/ncbi_servicep.h
/usr/include/ncbi/connect/ncbi_socket.h
/usr/include/ncbi/connect/ncbi_socket_connector.h
/usr/include/ncbi/connect/ncbi_socket_unix.h
/usr/include/ncbi/connect/ncbi_socketp.h
/usr/include/ncbi/connect/ncbi_types.h
/usr/include/ncbi/connect/ncbi_util.h
/usr/include/ncbi/connect/ncbi_version.h