/usr/lib/x86_64-linux-gnu/webaccounts-browser-extension/libwebaccounts.so is in webaccounts-extension-common 0.5-0ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/webaccounts-browser-extension/libwebaccounts-0.5.so