/usr/lib/x86_64-linux-gnu/libsensors-applet-plugin.so is in libsensors-applet-plugin-dev 3.0.0+git6-0.1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libsensors-applet-plugin.so.0.0.0