/usr/include/libfswatch/ is in libfswatch-dev 1.11.2+repack-10.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libfswatch/c/
/usr/include/libfswatch/c++/
/usr/include/libfswatch/c++/event.hpp
/usr/include/libfswatch/c++/filter.hpp
/usr/include/libfswatch/c++/inotify_monitor.hpp
/usr/include/libfswatch/c++/libfswatch_exception.hpp
/usr/include/libfswatch/c++/libfswatch_map.hpp
/usr/include/libfswatch/c++/libfswatch_set.hpp
/usr/include/libfswatch/c++/monitor.hpp
/usr/include/libfswatch/c++/path_utils.hpp
/usr/include/libfswatch/c++/poll_monitor.hpp
/usr/include/libfswatch/c++/string_utils.hpp
/usr/include/libfswatch/c/cevent.h
/usr/include/libfswatch/c/cfilter.h
/usr/include/libfswatch/c/cmonitor.h
/usr/include/libfswatch/c/error.h
/usr/include/libfswatch/c/libfswatch.h
/usr/include/libfswatch/c/libfswatch_log.h
/usr/include/libfswatch/c/libfswatch_types.h