This page stays hidden until the onShow event is triggered.
The event fires after either:
You can control the number of parallel fetches using the fetchCount parameter.
More fetches simulate heavier load and may increase the estimated LCP.
The timeout is meant to cap LCP growth, but when running Lighthouse with its default simulated throttling, the estimated LCP increases as the fetch count grows.
However, when using Lighthouse with DevTools-based throttling, LCP behaves as expected and does not grow with fetch count.