/usr/lib/x86_64-linux-gnu/libsigc-2.0.so is in libsigc++-2.0-dev 2.2.10-0.2ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libsigc-2.0.so.0.0.0
/usr/lib/x86_64-linux-gnu/libsigc-2.0.so.0.0.0