/usr/include/ql/experimental/barrieroption/ is in libquantlib0-dev 1.7.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ql/experimental/barrieroption/all.hpp
/usr/include/ql/experimental/barrieroption/analyticdoublebarrierbinaryengine.hpp
/usr/include/ql/experimental/barrieroption/analyticdoublebarrierengine.hpp
/usr/include/ql/experimental/barrieroption/binomialdoublebarrierengine.hpp
/usr/include/ql/experimental/barrieroption/discretizeddoublebarrieroption.hpp
/usr/include/ql/experimental/barrieroption/doublebarrieroption.hpp
/usr/include/ql/experimental/barrieroption/doublebarriertype.hpp
/usr/include/ql/experimental/barrieroption/perturbativebarrieroptionengine.hpp
/usr/include/ql/experimental/barrieroption/quantodoublebarrieroption.hpp
/usr/include/ql/experimental/barrieroption/vannavolgabarrierengine.hpp
/usr/include/ql/experimental/barrieroption/vannavolgadoublebarrierengine.hpp
/usr/include/ql/experimental/barrieroption/vannavolgainterpolation.hpp
/usr/include/ql/experimental/barrieroption/wulinyongdoublebarrierengine.hpp