The https://collector.openwebdocs.org project (v10.17.14) found new features shipping in Safari 27 beta (22625.1.18.11.5) on macOS 27.0 Beta (26A5353q) which was released today. Currently, the collector covers about 90% of BCD, so the following list might not be exhaustive. Also, if a feature is in Safari TP only, it is not considered here.

This PR contains 69 feature updates or additions and as soon as release notes are available, I can try to verify the findings.

• api.AnimationEvent.animation
• api.CredentialsContainer.get.identity_option
• api.CredentialsContainer.get.otp_option
• api.Document.ariaNotify
• api.Element.ariaNotify
• api.GPUDevice.uncapturederror_event
• api.GPUSupportedLimits.maxStorageBuffersInFragmentStage
• api.GPUSupportedLimits.maxStorageBuffersInVertexStage
• api.GPUSupportedLimits.maxStorageTexturesInFragmentStage
• api.GPUSupportedLimits.maxStorageTexturesInVertexStage
• api.HTMLAnchorElement.attributionSourceId (removal)
• api.HTMLModelElement
• api.HTMLModelElement.boundingBoxCenter
• api.HTMLModelElement.boundingBoxExtents
• api.HTMLModelElement.entityTransform
• api.HTMLModelElement.environmentMap
• api.HTMLModelElement.environmentMapReady
• api.HTMLModelElement.ready
• api.HTMLModelElement.stageMode
• api.HTMLTemplateElement.shadowRootSlotAssignment
• api.InstallEvent
• api.InstallEvent.InstallEvent
• api.InstallEvent.addRoutes
• api.PerformanceResourceTiming.workerCacheLookupStart
• api.PerformanceResourceTiming.workerFinalRouterSource
• api.PerformanceResourceTiming.workerMatchedRouterSource
• api.PerformanceResourceTiming.workerRouterEvaluationStart
• api.RTCRtpReceiver.jitterBufferTarget
• api.ReadableStream.from_static
• api.ReadableStream.values
• api.ReadableStream.@@asyncIterator
• api.TransitionEvent.animation
• api.WorkerNavigator.globalPrivacyControl
• css.properties.appearance.base-select
• css.properties.appearance.base-select.single_dropdown
• css.properties.block-size.stretch
• css.properties.flex-basis.stretch
• css.properties.flex.stretch
• css.properties.height.stretch
• css.properties.inline-size.stretch
• css.properties.max-block-size.stretch
• css.properties.max-height.stretch
• css.properties.max-inline-size.stretch
• css.properties.max-width.stretch
• css.properties.min-block-size.stretch
• css.properties.min-height.stretch
• css.properties.min-inline-size.stretch
• css.properties.min-width.stretch
• css.properties.overflow-anchor
• css.properties.overflow-anchor.auto
• css.properties.overflow-anchor.none
• css.properties.position-anchor.none
• css.properties.position-anchor.normal
• css.properties.position-visibility.anchor-valid
• css.properties.position-visibility.anchor-visible
• css.properties.text-autospace.insert
• css.properties.width.stretch
• css.selectors.checkmark
• css.selectors.picker-icon
• css.selectors.picker
• html.elements.model
• html.elements.model.autoplay
• html.elements.model.height
• html.elements.model.loop
• html.elements.model.src
• html.elements.model.stagemode
• html.elements.model.width
• http.headers.Sec-GPC
• webassembly.jspi