/usr/lib/x86_64-linux-gnu/ is in libroar-dev 1.0~beta11-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/libroarmidi.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/libroareio.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/libroardsp.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/libroar.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/libroarlight.pc
/usr/lib/x86_64-linux-gnu/ckport/
/usr/lib/x86_64-linux-gnu/ckport/db/
/usr/lib/x86_64-linux-gnu/ckport/db/libroar.ckport
/usr/lib/x86_64-linux-gnu/libroar.so
/usr/lib/x86_64-linux-gnu/libroarmidi.so
/usr/lib/x86_64-linux-gnu/libroarpulse-simple.so
/usr/lib/x86_64-linux-gnu/libroarpulse.so
/usr/lib/x86_64-linux-gnu/libroardsp.so
/usr/lib/x86_64-linux-gnu/libroaresd.so
/usr/lib/x86_64-linux-gnu/libsndio.so
/usr/lib/x86_64-linux-gnu/libroaross.so
/usr/lib/x86_64-linux-gnu/libroarsndio.so
/usr/lib/x86_64-linux-gnu/libroarlight.so
/usr/lib/x86_64-linux-gnu/libroareio.so