I often use the Performance Timeline in Chrome DevTools to record my page performance.
I use "Start profiling and reload page", which automatically starts and stops the recording.
The question is: When does DevTools decide to stop the recording?
I've noticed that it always continues to record at least a few hundred ms past the "Load"-event and tries to figure out when the page has gone "mostly idle".
But that's quite a fuzzy guess. I'd love to know if it relies on some performance event (like the one used in "time to interactive" in Lighthouse)?
Chrome devtools waits for 5 seconds after load
event (source) since Chrome 85. This is not documented so it may change without notice and did change in Chrome 85 from 3 seconds.
You can modify this behavior in your current debugging session:
Performance
panel/tabUI.panels.timeline.millisecondsToRecordAfterLoadEvent = 9001.