This is a testharness.js-based test. FAIL Verify XHR does not exist assert_unreached: unexpected rejection: Blocked unregister should not fail: Failed to get a frame with ServiceWorkerRegistration: The URL protocol of the current origin "https://web-platform.test:8444" from accessing a cross-origin frame. ('file://') is not supported. Reached unreachable code Harness: the test ran to completion.