/usr/share/lintian/overrides/liblxc1 is in liblxc1 3.0.1-0ubuntu1~18.04.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
no-symbols-control-file usr/lib/x86_64-linux-gnu/liblxc.so.*