/usr/lib/x86_64-linux-gnu/libtango.so is in libtango8-dev 8.1.2c+dfsg-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libtango.so.8.1.2
/usr/lib/x86_64-linux-gnu/libtango.so.8.1.2