/usr/lib/x86_64-linux-gnu/libtag.so is in libtag1-dev 1.9.1-2.4ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libtag.so.1
/usr/lib/x86_64-linux-gnu/libtag.so.1