/usr/lib/x86_64-linux-gnu/libtmglib.so is in libtmglib-dev 3.7.1-4ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libtmglib.so.3.7.1
/usr/lib/x86_64-linux-gnu/libtmglib.so.3.7.1