/usr/lib/x86_64-linux-gnu/libspectre.so is in libspectre-dev 0.2.8-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libspectre.so.1.1.8
/usr/lib/x86_64-linux-gnu/libspectre.so.1.1.8