/usr/include/ is in librandom123-dev 1.09+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/Random123/
/usr/include/Random123/MicroURNG.hpp
/usr/include/Random123/ReinterpretCtr.hpp
/usr/include/Random123/aes.h
/usr/include/Random123/array.h
/usr/include/Random123/ars.h
/usr/include/Random123/conventional/
/usr/include/Random123/conventional/Engine.hpp
/usr/include/Random123/conventional/gsl_cbrng.h
/usr/include/Random123/features/
/usr/include/Random123/features/clangfeatures.h
/usr/include/Random123/features/compilerfeatures.h
/usr/include/Random123/features/gccfeatures.h
/usr/include/Random123/features/iccfeatures.h
/usr/include/Random123/features/msvcfeatures.h
/usr/include/Random123/features/nvccfeatures.h
/usr/include/Random123/features/open64features.h
/usr/include/Random123/features/openclfeatures.h
/usr/include/Random123/features/sse.h
/usr/include/Random123/features/sunprofeatures.h
/usr/include/Random123/gsl_microrng.h
/usr/include/Random123/philox.h
/usr/include/Random123/threefry.h