/usr/include/ql/termstructures/yield/ is in libquantlib0-dev 1.1-2build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ql/termstructures/yield/all.hpp
/usr/include/ql/termstructures/yield/bondhelpers.hpp
/usr/include/ql/termstructures/yield/bootstraptraits.hpp
/usr/include/ql/termstructures/yield/discountcurve.hpp
/usr/include/ql/termstructures/yield/drifttermstructure.hpp
/usr/include/ql/termstructures/yield/fittedbonddiscountcurve.hpp
/usr/include/ql/termstructures/yield/flatforward.hpp
/usr/include/ql/termstructures/yield/forwardcurve.hpp
/usr/include/ql/termstructures/yield/forwardspreadedtermstructure.hpp
/usr/include/ql/termstructures/yield/forwardstructure.hpp
/usr/include/ql/termstructures/yield/impliedtermstructure.hpp
/usr/include/ql/termstructures/yield/nonlinearfittingmethods.hpp
/usr/include/ql/termstructures/yield/oisratehelper.hpp
/usr/include/ql/termstructures/yield/piecewiseyieldcurve.hpp
/usr/include/ql/termstructures/yield/piecewisezerospreadedtermstructure.hpp
/usr/include/ql/termstructures/yield/quantotermstructure.hpp
/usr/include/ql/termstructures/yield/ratehelpers.hpp
/usr/include/ql/termstructures/yield/zerocurve.hpp
/usr/include/ql/termstructures/yield/zerospreadedtermstructure.hpp
/usr/include/ql/termstructures/yield/zeroyieldstructure.hpp