navigator.scheduling.isInputPending is shipping by default in current Chrome stable (m87). Without user input, any page using isInputPending has a strong reason to believe yielding during long tasks won't improve user experience so it could keep on chugging instead.

This may have a large impact on any metric looking at long tasks (TBT, TTI) compared to what a real user would experience when loading the same page.

• There was a discussion in the WICG about how it should interact with the Long Tasks API and warnings against long tasks, as well if there should be a way to tell if isInputPending was called during a particular long task: Interaction with Long Tasks WICG/is-input-pending#37
• Chrome status entry