/usr/lib/swi-prolog/library/dialect/ciao/ is in swi-prolog-nox 6.6.4-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/swi-prolog/library/dialect/ciao/aggregates.pl
/usr/lib/swi-prolog/library/dialect/ciao/assertions.pl
/usr/lib/swi-prolog/library/dialect/ciao/basicmodes.pl
/usr/lib/swi-prolog/library/dialect/ciao/classic.pl
/usr/lib/swi-prolog/library/dialect/ciao/dcg.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/
/usr/lib/swi-prolog/library/dialect/ciao/engine/attributes.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/basic_props.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/basiccontrol.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/exceptions.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/exceptions_db.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/hiord_rt.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/internals.pl
/usr/lib/swi-prolog/library/dialect/ciao/engine/io_aux.pl
/usr/lib/swi-prolog/library/dialect/ciao/file_utils.pl
/usr/lib/swi-prolog/library/dialect/ciao/format.pl
/usr/lib/swi-prolog/library/dialect/ciao/freeze.pl
/usr/lib/swi-prolog/library/dialect/ciao/hiord.pl
/usr/lib/swi-prolog/library/dialect/ciao/hiordlib.pl
/usr/lib/swi-prolog/library/dialect/ciao/iso_misc.pl
/usr/lib/swi-prolog/library/dialect/ciao/isomodes.pl
/usr/lib/swi-prolog/library/dialect/ciao/lists.pl
/usr/lib/swi-prolog/library/dialect/ciao/llists.pl
/usr/lib/swi-prolog/library/dialect/ciao/nativeprops.pl
/usr/lib/swi-prolog/library/dialect/ciao/nortchecks.pl
/usr/lib/swi-prolog/library/dialect/ciao/odd.pl
/usr/lib/swi-prolog/library/dialect/ciao/prolog_flags.pl
/usr/lib/swi-prolog/library/dialect/ciao/read.pl
/usr/lib/swi-prolog/library/dialect/ciao/regtypes/
/usr/lib/swi-prolog/library/dialect/ciao/regtypes.pl
/usr/lib/swi-prolog/library/dialect/ciao/regtypes/regtypes_tr.pl
/usr/lib/swi-prolog/library/dialect/ciao/sockets.pl
/usr/lib/swi-prolog/library/dialect/ciao/sort.pl
/usr/lib/swi-prolog/library/dialect/ciao/streams.pl
/usr/lib/swi-prolog/library/dialect/ciao/strings.pl
/usr/lib/swi-prolog/library/dialect/ciao/system.pl
/usr/lib/swi-prolog/library/dialect/ciao/terms.pl
/usr/lib/swi-prolog/library/dialect/ciao/terms_check.pl
/usr/lib/swi-prolog/library/dialect/ciao/terms_vars.pl
/usr/lib/swi-prolog/library/dialect/ciao/unittestdecls.pl
/usr/lib/swi-prolog/library/dialect/ciao/unittestprops.pl
/usr/lib/swi-prolog/library/dialect/ciao/write.pl