E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness — a framework Google uses to judge content quality, especially for important topics.
E-E-A-T is not one score but a set of signals. It matters most for health, finance and other high-stakes ("YMYL") topics.
Not a single score, but the signals behind it influence rankings.
The first E (Experience) was added to reward first-hand knowledge.