Ordinarily, idle service workers are forcefully slaughtered as an improvement, to keep code from running out of sight when it's not required. Chrome finds a way to recognize whether DevTools are open, and when it is, won't kill the service worker automatically. The supposition that will be that if an engineer is utilizing DevTools, they may be troubleshooting or generally looking at the service worker's behavior, and killing the service worker would baffle the designer. Expanding the lifetime of the service worker used to be done quietly, however as portrayed here, for as far back as hardly any adaptations of Chrome, the message
Service Worker termination by a timeout timer was canceled because DevTools is attached.
is logged to the console to tell the designer that the service worker would typically have been killed, however the job to kill it was dropped due to DevTools being open.