/usr/ is in libelemental-dev 1.2.0-11.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libelemental/
/usr/include/
/usr/include/libelemental/element.hh
/usr/include/libelemental/element.tcc
/usr/include/libelemental/misc/
/usr/include/libelemental/misc/extras.hh
/usr/include/libelemental/misc/ucompose.hh
/usr/include/libelemental/misc/ucompose.tcc
/usr/include/libelemental/properties.hh
/usr/include/libelemental/table.hh
/usr/include/libelemental/value-types.hh
/usr/include/libelemental/value.hh
/usr/include/libelemental/value.tcc
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/libelemental.a
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/libelemental.pc
/usr/share/
/usr/share/doc/
/usr/share/doc/libelemental-dev/
/usr/share/doc/libelemental-dev/copyright
/usr/lib/x86_64-linux-gnu/libelemental.so
/usr/share/doc/libelemental-dev/changelog.Debian.gz