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conformance · v148

v148 · container-timing — 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://wicg.github.io/container-timing/ chromestatus: #5110962817073152 generated 2026-06-06T20:00:34Z by codex-container-timing-mcp
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id contract kind verdict detail
performance-observer-exists PerformanceObserver is the delivery mechanism used when Container Timing is enabled. spec ↗ exists
containertiming-attribute-reflects The containertiming content attribute stores the identifier that becomes PerformanceContainerTiming.identifier. spec ↗ script
containertiming-ignore-attribute-reflects The containertiming-ignore content attribute can mark an ignored subtree for ancestor container timing. spec ↗ script
performance-container-timing-constructor-gates-native-support Origin-trial native support is detected through the PerformanceContainerTiming constructor recommended by Chrome. spec ↗ script
performance-container-timing-prototype-fields When native support is enabled, PerformanceContainerTiming exposes the identifier, first-render, size, root, last-painted, and paint timestamp fields. spec ↗ script
native-observer-registration-or-clean-unsupported When native support is enabled, PerformanceObserver can register type: 'container'; otherwise the unsupported browser path remains clean. spec ↗ script