/usr/lib/x86_64-linux-gnu/libQt5Bluetooth.so is in qtconnectivity5-dev 5.5.1-2build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libQt5Bluetooth.so.5.5.1
/usr/lib/x86_64-linux-gnu/libQt5Bluetooth.so.5.5.1