Facebook employs robust server-side access control lists (ACLs). When a user attempts to access a profile, the server checks the relationship between the requester and the target. If the content is marked "Private" or "Friends Only," the server simply does not send the data (images, posts, biographical details) to the requester's device. There is no "hidden" data stream that a browser extension or script can "unlock" locally; the data never leaves the server.
If you're looking to reconnect with someone or verify their identity, consider using legitimate and respectful methods. Remember, if someone has chosen to make their profile private, it's for a reason. Respecting their privacy is not only the right thing to do but also crucial for maintaining a safe and respectful online community. facebook private profile viewer free exclusive
Avoid websites or apps that promise: