/usr/lib/x86_64-linux-gnu/libqtubuntu-media-signals.so is in libqtubuntu-media-signals-dev 0.3+15.10.20150710-0ubuntu2~gcc5.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libqtubuntu-media-signals.so.2