You can now see your real user data for Time to First Byte (TTFB) and Interaction to Next Paint (INP) using Core Web Vitals Test:
Core Web Vitals report for calibreapp.com domain.
Time to First Byte is critical to track as it can have a cascading, adverse effect on page load and speed. Interaction to Next Paint is a new, experimental metric measuring the longest observed delay between user interaction and the response on your page. While these metrics are not included in the Core Web Vitals set now, we’d recommend adding them to your “to track” list.