/usr/lib/x86_64-linux-gnu/libbrotlicommon.so is in libbrotli-dev 1.0.3-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libbrotlicommon.so.1
/usr/lib/x86_64-linux-gnu/libbrotlicommon.so.1