/usr/include/ql/cashflows/ is in libquantlib0-dev 1.1-2build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ql/cashflows/all.hpp
/usr/include/ql/cashflows/averagebmacoupon.hpp
/usr/include/ql/cashflows/capflooredcoupon.hpp
/usr/include/ql/cashflows/capflooredinflationcoupon.hpp
/usr/include/ql/cashflows/cashflows.hpp
/usr/include/ql/cashflows/cashflowvectors.hpp
/usr/include/ql/cashflows/cmscoupon.hpp
/usr/include/ql/cashflows/conundrumpricer.hpp
/usr/include/ql/cashflows/coupon.hpp
/usr/include/ql/cashflows/couponpricer.hpp
/usr/include/ql/cashflows/digitalcmscoupon.hpp
/usr/include/ql/cashflows/digitalcoupon.hpp
/usr/include/ql/cashflows/digitaliborcoupon.hpp
/usr/include/ql/cashflows/dividend.hpp
/usr/include/ql/cashflows/duration.hpp
/usr/include/ql/cashflows/fixedratecoupon.hpp
/usr/include/ql/cashflows/floatingratecoupon.hpp
/usr/include/ql/cashflows/iborcoupon.hpp
/usr/include/ql/cashflows/indexedcashflow.hpp
/usr/include/ql/cashflows/inflationcoupon.hpp
/usr/include/ql/cashflows/inflationcouponpricer.hpp
/usr/include/ql/cashflows/overnightindexedcoupon.hpp
/usr/include/ql/cashflows/rangeaccrual.hpp
/usr/include/ql/cashflows/replication.hpp
/usr/include/ql/cashflows/simplecashflow.hpp
/usr/include/ql/cashflows/timebasket.hpp
/usr/include/ql/cashflows/yoyinflationcoupon.hpp