The short answer
E-E-A-T stands for experience, expertise, authoritativeness and trust. It comes from the guidelines Google's human quality raters use, and Google calls trust the most important part. It isn't a single score you can measure.
What you can check is whether a page shows the signals people look for before trusting it: who wrote it, when it was checked, how to reach the business, and where its facts come from. That's what this tool reads.
Questions
Is E-E-A-T a ranking factor?
Not as one score. Google's raters use it to judge results, and their ratings don't directly change rankings. It describes the kind of content Google's systems aim to show, so the signals still matter.
Which pages need it most?
Pages about health, money, legal matters or safety, where wrong information can hurt someone. Google looks hardest for trust there.
Can I just add an author name?
Use a real person with a short bio and a link to an About page. Google warns against made-up author profiles, such as AI-generated photos or false credentials.
Does this tool change my page?
No. It reads one public page and shows what it found, with suggested code to paste yourself.