The "extra quality" promise is often delivered via a downloadable .exe file (Windows) or .apk (Android). These files are almost always malware. Types include:
There is no known, functioning software that can reliably view a fully private Facebook profile with "extra quality" or any quality. If such a vulnerability existed, Facebook’s (now Meta’s) massive bug bounty program would have patched it within hours.
Check if you have friends in common. Sometimes you can see tagged photos or comments made by the private user on a mutual friend’s public posts.
: Some browser extensions, such as the Facebook profile picture viewer on the Chrome Web Store, allow you to see a larger, Full HD version of a profile picture that is normally displayed as a small thumbnail.
: Some scams show a fake list of random friends or users to make you believe the tool is working while they harvest your data in the background.
Facebook spends billions of dollars annually on security. If a vulnerability (a "bug") exists that allows private profile viewing, Facebook pays ethical hackers thousands of dollars (via their Bug Bounty Program) to fix it within hours. No working exploit stays online for the public to use.