/usr/include/ is in libbelcard-dev 1.0.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/belcard/
/usr/include/belcard/belcard.hpp
/usr/include/belcard/belcard_addressing.hpp
/usr/include/belcard/belcard_calendar.hpp
/usr/include/belcard/belcard_communication.hpp
/usr/include/belcard/belcard_explanatory.hpp
/usr/include/belcard/belcard_general.hpp
/usr/include/belcard/belcard_generic.hpp
/usr/include/belcard/belcard_geographical.hpp
/usr/include/belcard/belcard_identification.hpp
/usr/include/belcard/belcard_organizational.hpp
/usr/include/belcard/belcard_params.hpp
/usr/include/belcard/belcard_parser.hpp
/usr/include/belcard/belcard_property.hpp
/usr/include/belcard/belcard_rfc6474.hpp
/usr/include/belcard/belcard_security.hpp
/usr/include/belcard/belcard_utils.hpp
/usr/include/belcard/vcard_grammar.hpp