/usr/lib/x86_64-linux-gnu/libgnuradio-qtgui.so is in gnuradio-dev 3.7.10.1-2+b3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgnuradio-qtgui.so.3.7.10
/usr/lib/x86_64-linux-gnu/libgnuradio-qtgui.so.3.7.10