The same detection a native shell lights up when it hosts this code. Green means the platform answered.
navigator.sharecheckingnavigator.vibratecheckingnavigator.clipboardcheckingnavigator.geolocationcheckingnavigator.storage.estimatecheckingdisplay-mode: standalonecheckingserviceWorker.controllercheckingmaxTouchPointscheckingEach button calls the real platform API and reports what came back.
Registering the service worker...