/usr/include/ is in libcpprest-dev 2.9.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/cpprest/asyncrt_utils.h
/usr/include/cpprest/
/usr/include/cpprest/astreambuf.h
/usr/include/cpprest/base_uri.h
/usr/include/cpprest/containerstream.h
/usr/include/cpprest/details/
/usr/include/cpprest/details/SafeInt3.hpp
/usr/include/cpprest/details/basic_types.h
/usr/include/cpprest/details/cpprest_compat.h
/usr/include/cpprest/details/fileio.h
/usr/include/cpprest/details/http_constants.dat
/usr/include/cpprest/details/http_helpers.h
/usr/include/cpprest/details/http_server.h
/usr/include/cpprest/details/http_server_api.h
/usr/include/cpprest/details/http_server_asio.h
/usr/include/cpprest/details/http_server_httpsys.h
/usr/include/cpprest/details/nosal.h
/usr/include/cpprest/details/resource.h
/usr/include/cpprest/details/uri_parser.h
/usr/include/cpprest/details/web_utilities.h
/usr/include/cpprest/details/x509_cert_utilities.h
/usr/include/cpprest/filestream.h
/usr/include/cpprest/http_client.h
/usr/include/cpprest/http_headers.h
/usr/include/cpprest/http_listener.h
/usr/include/cpprest/http_msg.h
/usr/include/cpprest/interopstream.h
/usr/include/cpprest/json.h
/usr/include/cpprest/oauth1.h
/usr/include/cpprest/oauth2.h
/usr/include/cpprest/producerconsumerstream.h
/usr/include/cpprest/rawptrstream.h
/usr/include/cpprest/streams.h
/usr/include/cpprest/uri.h
/usr/include/cpprest/uri_builder.h
/usr/include/cpprest/version.h
/usr/include/cpprest/ws_client.h
/usr/include/cpprest/ws_msg.h
/usr/include/pplx/
/usr/include/pplx/pplx.h
/usr/include/pplx/pplxcancellation_token.h
/usr/include/pplx/pplxconv.h
/usr/include/pplx/pplxinterface.h
/usr/include/pplx/pplxlinux.h
/usr/include/pplx/pplxtasks.h
/usr/include/pplx/pplxwin.h
/usr/include/pplx/threadpool.h