/usr/include/sc/math/optimize/ is in libsc-dev 2.3.1-18+deb9u1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/sc/math/optimize/LIBS.h
/usr/include/sc/math/optimize/conv.h
/usr/include/sc/math/optimize/diis.h
/usr/include/sc/math/optimize/efc.h
/usr/include/sc/math/optimize/function.h
/usr/include/sc/math/optimize/gdiis.h
/usr/include/sc/math/optimize/linkage.h
/usr/include/sc/math/optimize/mcsearch.h
/usr/include/sc/math/optimize/newton.h
/usr/include/sc/math/optimize/opt.h
/usr/include/sc/math/optimize/qnewton.h
/usr/include/sc/math/optimize/scextrap.h
/usr/include/sc/math/optimize/scextrapmat.h
/usr/include/sc/math/optimize/steep.h
/usr/include/sc/math/optimize/transform.h
/usr/include/sc/math/optimize/update.h