/usr/lib/x86_64-linux-gnu/libthai.so is in libthai-dev 0.1.20-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libthai.so.0.2.0
/usr/lib/x86_64-linux-gnu/libthai.so.0.2.0