/usr/include/ibus-1.0/ is in libibus-1.0-dev 1.5.17-3ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ibus-1.0/ibus.h
/usr/include/ibus-1.0/ibusattribute.h
/usr/include/ibus-1.0/ibusattrlist.h
/usr/include/ibus-1.0/ibusbus.h
/usr/include/ibus-1.0/ibuscomponent.h
/usr/include/ibus-1.0/ibusconfig.h
/usr/include/ibus-1.0/ibusconfigservice.h
/usr/include/ibus-1.0/ibusdebug.h
/usr/include/ibus-1.0/ibusemoji.h
/usr/include/ibus-1.0/ibusengine.h
/usr/include/ibus-1.0/ibusenginedesc.h
/usr/include/ibus-1.0/ibusenginesimple.h
/usr/include/ibus-1.0/ibusenumtypes.h
/usr/include/ibus-1.0/ibuserror.h
/usr/include/ibus-1.0/ibusfactory.h
/usr/include/ibus-1.0/ibushotkey.h
/usr/include/ibus-1.0/ibusinputcontext.h
/usr/include/ibus-1.0/ibuskeymap.h
/usr/include/ibus-1.0/ibuskeys.h
/usr/include/ibus-1.0/ibuskeysyms-compat.h
/usr/include/ibus-1.0/ibuskeysyms.h
/usr/include/ibus-1.0/ibuslookuptable.h
/usr/include/ibus-1.0/ibusobject.h
/usr/include/ibus-1.0/ibusobservedpath.h
/usr/include/ibus-1.0/ibuspanelservice.h
/usr/include/ibus-1.0/ibusproperty.h
/usr/include/ibus-1.0/ibusproplist.h
/usr/include/ibus-1.0/ibusproxy.h
/usr/include/ibus-1.0/ibusregistry.h
/usr/include/ibus-1.0/ibusserializable.h
/usr/include/ibus-1.0/ibusservice.h
/usr/include/ibus-1.0/ibusshare.h
/usr/include/ibus-1.0/ibustext.h
/usr/include/ibus-1.0/ibustypes.h
/usr/include/ibus-1.0/ibusutil.h
/usr/include/ibus-1.0/ibusversion.h
/usr/include/ibus-1.0/ibusxml.h