/usr/include/ is in libxmlrpc-core-c3-dev 1.33.14-0.2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/xmlrpc-c/
/usr/include/xmlrpc-c/util.h
/usr/include/xmlrpc-c/base.h
/usr/include/xmlrpc-c/abyss.h
/usr/include/xmlrpc-c/server_w32httpsys.h
/usr/include/xmlrpc-c/abyss_winsock.h
/usr/include/xmlrpc-c/c_util.h
/usr/include/xmlrpc-c/transport.h
/usr/include/xmlrpc-c/oldxmlrpc.h
/usr/include/xmlrpc-c/inttypes.h
/usr/include/xmlrpc-c/client.h
/usr/include/xmlrpc-c/server_abyss.h
/usr/include/xmlrpc-c/json.h
/usr/include/xmlrpc-c/server.h
/usr/include/xmlrpc-c/server_cgi.h
/usr/include/xmlrpc-c/abyss_unixsock.h
/usr/include/xmlrpc-c/config.h
/usr/include/xmlrpc-c/client_global.h
/usr/include/xmlrpc_server_w32httpsys.h
/usr/include/xmlrpc_cgi.h
/usr/include/XmlRpcCpp.h
/usr/include/xmlrpc_client.h
/usr/include/xmlrpc_abyss.h
/usr/include/xmlrpc_server.h
/usr/include/xmlrpc.h