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conformance · v132

v132 · resource-timing-revert-responsestart-change-and-introduce-firstresponseheadersst — conformance probe

6 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.

browser: spec: https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-finalresponseheadersstart chromestatus: #5158830722514944 generated 2026-06-01T08:32:00Z by conformance-author-v1-subagent
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id contract kind verdict detail
performance-resource-timing-class PerformanceResourceTiming is exposed. exists
response-start-property-exists PerformanceResourceTiming.prototype.responseStart is exposed. spec ↗ script
first-response-headers-start-property PerformanceResourceTiming.prototype.firstResponseHeadersStart is exposed — the new timestamp. spec ↗ script
final-response-headers-start-property PerformanceResourceTiming.prototype.finalResponseHeadersStart is exposed — paired with firstResponseHeadersStart for early-hints visibility. spec ↗ script
supported-entry-types-include-resource 'resource' is an advertised supported entry type. script
response-start-is-number responseStart on resource entries reads as a number (DOMHighResTimeStamp). spec ↗ script