/usr/include/ircd-hybrid-8/ is in hybrid-dev 1:8.1.13.dfsg.1-1.
This file is owned by root:root, with mode 0o775.
..
/usr/include/ircd-hybrid-8/channel.h
/usr/include/ircd-hybrid-8/channel_mode.h
/usr/include/ircd-hybrid-8/client.h
/usr/include/ircd-hybrid-8/conf.h
/usr/include/ircd-hybrid-8/conf_class.h
/usr/include/ircd-hybrid-8/conf_db.h
/usr/include/ircd-hybrid-8/dbuf.h
/usr/include/ircd-hybrid-8/defaults.h
/usr/include/ircd-hybrid-8/event.h
/usr/include/ircd-hybrid-8/fdlist.h
/usr/include/ircd-hybrid-8/hash.h
/usr/include/ircd-hybrid-8/hook.h
/usr/include/ircd-hybrid-8/hostmask.h
/usr/include/ircd-hybrid-8/irc_res.h
/usr/include/ircd-hybrid-8/irc_reslib.h
/usr/include/ircd-hybrid-8/irc_string.h
/usr/include/ircd-hybrid-8/ircd.h
/usr/include/ircd-hybrid-8/ircd_defs.h
/usr/include/ircd-hybrid-8/ircd_getopt.h
/usr/include/ircd-hybrid-8/ircd_signal.h
/usr/include/ircd-hybrid-8/list.h
/usr/include/ircd-hybrid-8/listener.h
/usr/include/ircd-hybrid-8/log.h
/usr/include/ircd-hybrid-8/memory.h
/usr/include/ircd-hybrid-8/mempool.h
/usr/include/ircd-hybrid-8/modules.h
/usr/include/ircd-hybrid-8/motd.h
/usr/include/ircd-hybrid-8/numeric.h
/usr/include/ircd-hybrid-8/packet.h
/usr/include/ircd-hybrid-8/parse.h
/usr/include/ircd-hybrid-8/patchlevel-debian.h
/usr/include/ircd-hybrid-8/patchlevel.h
/usr/include/ircd-hybrid-8/restart.h
/usr/include/ircd-hybrid-8/resv.h
/usr/include/ircd-hybrid-8/rng_mt.h
/usr/include/ircd-hybrid-8/rsa.h
/usr/include/ircd-hybrid-8/s_auth.h
/usr/include/ircd-hybrid-8/s_bsd.h
/usr/include/ircd-hybrid-8/s_gline.h
/usr/include/ircd-hybrid-8/s_misc.h
/usr/include/ircd-hybrid-8/s_serv.h
/usr/include/ircd-hybrid-8/s_user.h
/usr/include/ircd-hybrid-8/send.h
/usr/include/ircd-hybrid-8/serno.h
/usr/include/ircd-hybrid-8/stdinc.h
/usr/include/ircd-hybrid-8/supported.h
/usr/include/ircd-hybrid-8/userhost.h
/usr/include/ircd-hybrid-8/watch.h
/usr/include/ircd-hybrid-8/whowas.h