/usr/lib/x86_64-linux-gnu/libindicator3.so is in libindicator3-dev 16.10.0+18.04.20180321.1-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libindicator3.so.7.0.0
/usr/lib/x86_64-linux-gnu/libindicator3.so.7.0.0