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conformance · v140
v140 · serviceworkerautopreload-browser-mode / bootstrap-cost — conformance probe
3 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.
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pass
0
fail
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blocked
3
total
| id | contract | kind | verdict | detail |
|---|---|---|---|---|
response-can-carry-an-attribution-header |
Every lane on this page is attributed by a header the fetch handler sets, not inferred from timing. If a synthesised Response could not carry a readable custom header, the page would be guessing which side answered. spec ↗ | script | … | |
service-worker-registration-is-available |
The page registers a worker and waits for it to claim the client before measuring. Without registration there are no routes and the three lanes would be indistinguishable. spec ↗ | typeof | … | |
performance-now-is-monotonic-enough-to-time-a-fetch |
The lane timings are performance.now deltas around a fetch. A clock that could go backwards would make a negative measurement possible and the comparison worthless. spec ↗ | script | … |