/usr/lib/x86_64-linux-gnu/libwebauth.so is in libwebauth-dev 4.6.1-1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libwebauth.so.11.0.0
/usr/lib/x86_64-linux-gnu/libwebauth.so.11.0.0