Facebook's privacy settings are enforced server-side. That means the restricted content never reaches your browser unless you're authorized to see it. No third-party tool can override Facebook's access controls without exploiting a security vulnerability — and if such a vulnerability existed, Facebook would patch it quickly, and using it would be illegal in most jurisdictions.
Some readers might think: "But what about real hacking tools? Couldn't a developer bypass Facebook's privacy?" facebook locked profile viewer online
If you truly need to see someone's locked profile content, there are only a few safe and legitimate methods: The Locked Profile Method 2: Ask a Mutual