9. What are Fingerprint Checkers and is it true that they guarantee complete anonymity?

These are online tools that collect and display a set of data that a web browser gives to sites. In practice, it’s not just one «fingerprint» but many small details: version and User Agent string, list and visible font properties, screen settings, time zone, WebGL resolution, canvas rendering results, enabled plugins, and more. 

How checkers work and why they are needed

When visiting a checker site, the script sequentially queries the available browser APIs, accesses canvas and WebGL, and tries to determine the list of fonts and other parameters. The checker collects this data and shows how unique your profile is in the collected database, and sometimes which fields make you distinguishable.

Do the checkers guarantee complete anonymity?

No. They are only a diagnostic tool, they show what data sites are collecting and how much you «stand out». They do not make you anonymous. Moreover, by taking the test, you can provide additional markers (like unique canvas responses) if the checker feeds the results into a shared dataset. Even if the checker shows low uniqueness now, with repeated visits to different sites, combinations of attributes and behavioral signals can still allow you to gather enough information for tracking. In addition, there are correlation techniques to link activity on different resources.

To keep your true digital identity a secret, use the 0DETECT anti-detect browser.