/usr/include/ql/processes/ is in libquantlib0-dev 1.12-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ql/processes/all.hpp
/usr/include/ql/processes/batesprocess.hpp
/usr/include/ql/processes/blackscholesprocess.hpp
/usr/include/ql/processes/endeulerdiscretization.hpp
/usr/include/ql/processes/eulerdiscretization.hpp
/usr/include/ql/processes/forwardmeasureprocess.hpp
/usr/include/ql/processes/g2process.hpp
/usr/include/ql/processes/geometricbrownianprocess.hpp
/usr/include/ql/processes/gjrgarchprocess.hpp
/usr/include/ql/processes/gsrprocess.hpp
/usr/include/ql/processes/gsrprocesscore.hpp
/usr/include/ql/processes/hestonprocess.hpp
/usr/include/ql/processes/hullwhiteprocess.hpp
/usr/include/ql/processes/hybridhestonhullwhiteprocess.hpp
/usr/include/ql/processes/jointstochasticprocess.hpp
/usr/include/ql/processes/merton76process.hpp
/usr/include/ql/processes/mfstateprocess.hpp
/usr/include/ql/processes/ornsteinuhlenbeckprocess.hpp
/usr/include/ql/processes/squarerootprocess.hpp
/usr/include/ql/processes/stochasticprocessarray.hpp