Definition: A browser metric that measures how long it takes for the page to visually update after a user interacts with it, such as a click, tap or key press. It is the responsiveness signal within Google's Core Web Vitals.
So what? It shows whether a page feels responsive to the person using it, across their interactions rather than just the first one.
Example: A user taps "Add to basket" and the button takes nearly a second to show any change because the browser is busy running scripts.
