/usr/include/leatherman/ is in libleatherman-dev 1.4.0+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/leatherman/curl/
/usr/include/leatherman/curl/client.hpp
/usr/include/leatherman/curl/export.h
/usr/include/leatherman/curl/request.hpp
/usr/include/leatherman/curl/response.hpp
/usr/include/leatherman/dynamic_library/
/usr/include/leatherman/dynamic_library/dynamic_library.hpp
/usr/include/leatherman/execution/
/usr/include/leatherman/execution/execution.hpp
/usr/include/leatherman/file_util/
/usr/include/leatherman/file_util/directory.hpp
/usr/include/leatherman/file_util/file.hpp
/usr/include/leatherman/json_container/
/usr/include/leatherman/json_container/json_container.hpp
/usr/include/leatherman/locale/
/usr/include/leatherman/locale/locale.hpp
/usr/include/leatherman/logging/
/usr/include/leatherman/logging/logging.hpp
/usr/include/leatherman/ruby/
/usr/include/leatherman/ruby/api.hpp
/usr/include/leatherman/util/
/usr/include/leatherman/util/environment.hpp
/usr/include/leatherman/util/option_set.hpp
/usr/include/leatherman/util/posix/
/usr/include/leatherman/util/posix/scoped_descriptor.hpp
/usr/include/leatherman/util/regex.hpp
/usr/include/leatherman/util/scope_exit.hpp
/usr/include/leatherman/util/scoped_env.hpp
/usr/include/leatherman/util/scoped_resource.hpp
/usr/include/leatherman/util/strings.hpp
/usr/include/leatherman/util/time.hpp
/usr/include/leatherman/util/timer.hpp
/usr/include/leatherman/util/uri.hpp
/usr/include/leatherman/util/windows/
/usr/include/leatherman/util/windows/scoped_handle.hpp