Official documentation explicitly states that Facebook does not allow users to track who views their profiles, nor do they permit third-party apps to provide this data.
The phrase "" refers to a category of third-party software—often marketed as "portable" because they don't require traditional installation—that claims to allow users to view private Facebook profiles without an account or notification . Critical Safety Warning
Let's break down what people are actually looking for when they type this phrase into a search engine.
While you cannot see who views your profile, you can see how your profile looks to the public (i.e., anonymous viewers). This is an official Facebook feature.