/usr/lib/x86_64-linux-gnu/libxcb-sync.so is in libxcb-sync-dev 1.12-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1.0.0
/usr/lib/x86_64-linux-gnu/libxcb-sync.so.1.0.0