Manifest position 967 · CrUX rank bucket 1000

https://www.youtube.com

Coverage complete

Coverage-complete audit of anonymous public home, search, watch, mobile and error states; signed-in, upload, purchase and creator-studio flows excluded.

Attempts

1 / 3

Judged checks

58 / 58

Blocked

Not run

This report has no published overall score. Blocked and not-run checks are not passes. A coverage-complete report means every check has a judged outcome; it does not mean every check passed.

All 58 atomic check outcomes

Principle / check	Status	Confidence	Evidence or reason
respect-user-preferences `respects-color-scheme`	issues	high	Desktop screenshots under default and prefers-color-scheme: dark are pixel-identical in treatment: the consent surface remains white and computed color-scheme is normal. F1 medium: The consent and anonymous entry experience ignore the system dark-mode preference.
respect-user-preferences `respects-reduced-motion`	pass	high	The reduced-motion probe found 26 prefers-reduced-motion media rules and zero running animations in the observed consent/home state.
respect-user-preferences `respects-contrast`	issues	high	The prefers-contrast screenshot did not alter the surface, and Lighthouse reported color-contrast and link-in-text-block failures. F2 medium: High-contrast preference is not reflected and baseline contrast defects remain.
implement-natural-interactions `view-transitions`	pass	high	The search-page CSS probe found active view-transition names root, metadata, and secondary-column, direct evidence of declarative route/state transition participation.
implement-natural-interactions `scroll-driven-animations`	not-applicable	high	No scroll-linked animation was present on the representative home, search, or watch states, so there was no scroll-driven implementation to evaluate.
implement-natural-interactions `physical-gestures`	pass	medium	The watch page uses native video controls and the responsive page retained platform scrolling without horizontal overflow; no custom pointer-drag layer displaced platform behavior.
provide-guided-navigation `scroll-state-aware-chrome`	pass	high	Search and watch screenshots show persistent masthead/sidebar orientation plus filter and chapter states that remain visually anchored to the current context.
provide-guided-navigation `anchored-positioning`	pass	high	The consent modal and visible menus remained centered/in-bounds at desktop and mobile sizes; no clipped overlay was observed.
provide-guided-navigation `directs-attention`	pass	high	Search results expose selected filter state, “Now playing”, chapters, and clear video titles; the watch page preserves current title and playback state.
maximize-content-reduce-noise `no-intrusive-interruptions`	issues	high	Every fresh home, search, and watch capture was covered by a large consent dialog; on mobile it filled the viewport and pushed all actions below the fold. F3 high: A full consent interstitial obscures every audited archetype on a fresh anonymous visit.
maximize-content-reduce-noise `semantic-dismissible-primitives`	pass	high	DOM inspection found dialog roles and explicit Reject all, Accept all, More options, privacy, and terms controls; the overlay is keyboard-addressable and dismissible.
maximize-content-reduce-noise `reduced-chrome`	pass	high	Behind the consent overlay, home/search/watch layouts devote the main region to recommendations, results, or video content with a compact masthead and collapsible navigation.
adapt-to-the-form-factor `responsive-no-horizontal-scroll`	pass	high	At 360x800, layout reported scrollWidth=clientWidth=360 and horizontalOverflowPx=0 with a valid viewport meta tag.
adapt-to-the-form-factor `component-level-responsiveness`	pass	medium	The live stylesheet probe found a container-query rule, and desktop/mobile captures show the consent and app chrome reflowing to the available width.
adapt-to-the-form-factor `input-modality-aware`	issues	high	The control probe found visible primary controls only 24x24 CSS px (Guide and Settings), while Lighthouse also failed the restrictive viewport scaling audit. F20 medium: Several prominent controls expose only 24×24 CSS-pixel hit areas.
support-core-task-success `clear-purpose-and-primary-action`	pass	high	Search and watch probes expose descriptive titles, video result links, Play, Search, and Go to home; page purpose and next action are explicit.
support-core-task-success `primary-flow-completion`	issues	high	The search-to-watch content exists, but an anonymous fresh session is interrupted by the full consent decision on every tested archetype before the primary content can be used. F4 high: The anonymous search-to-watch journey is gated by an oversized consent decision before content can be used.
support-core-task-success `clear-system-state-and-recovery`	pass	high	An invalid watch URL rendered “This video isn’t available any more” with a GO TO HOME recovery action; home also explains history-off state and offers Update setting.
be-fast-and-stable `good-core-web-vitals`	issues	high	Lighthouse measured FCP 6.5s, LCP 8.5s, Speed Index 13.4s, TBT 240ms, and performance score 0.51; trace LCP was 4.18s. F5 high: Cold-load performance is well outside the good LCP range.
be-fast-and-stable `visual-stability`	pass	high	The mobile layout observer measured CLS 0.000089 and Lighthouse CLS was 0.001, both comfortably stable.
be-fast-and-stable `efficient-main-thread`	issues	high	Trace recorded four long tasks, longest 268.78ms and TBT 275.52ms; Lighthouse reported 2.1s main-thread work. F6 high: Large main-thread tasks delay responsiveness.
be-fast-and-stable `efficient-resource-delivery`	issues	high	HAR recorded 144 requests and 4,057,297 transferred bytes, including 3,042,094 bytes of script and parser-inserted high-priority scripts/styles; Lighthouse flagged redirects, document latency, dependency chains, and render blocking. F7 high: The entry state ships a 4MB, script-heavy dependency graph before consent.
be-fast-and-stable `trim-unused-and-duplicate-code`	issues	high	Lighthouse estimated 643KiB unused JavaScript and 156KiB unused CSS; the largest JS response was 2.11MB transferred. F8 medium: Large amounts of downloaded JS and CSS are unused on the audited state.
be-inclusive `names-roles-labels`	issues	high	Lighthouse accessibility score was 0.85 and failed visible-label/accessibility-name matching plus unlabeled select controls. F9 medium: Some controls expose mismatched or missing accessible names.
be-inclusive `sufficient-contrast`	issues	high	Lighthouse directly failed color-contrast and links-distinguishable-by-color audits on the loaded experience. F10 medium: Text/link contrast does not consistently meet accessible minimums.
be-inclusive `structure-and-focus`	pass	high	The DOM exposes Skip navigation, named Search/Settings/Sign in controls, dialog actions, video controls, and ordered result headings; keyboard-oriented labels are present.
be-inclusive `legible-text`	pass	high	Desktop and mobile screenshots show readable 14–16px body copy, clear hierarchy, and no clipped lines; the mobile consent copy wraps within the viewport.
be-inclusive `zoom-reflow-targets-and-media`	issues	high	Lighthouse failed meta-viewport because scaling is constrained below its accessible threshold; the watch player reported captions unavailable in the tested state. F11 high: The viewport policy restricts user scaling.
follow-best-practices `no-console-errors`	issues	high	Lighthouse directly reported browser console errors during load. F12 medium: The page logs browser errors during a normal load.
follow-best-practices `sound-document-and-assets`	pass	high	Runtime probe found HTML doctype, UTF-8 charset, valid viewport, and negligible CLS; rendered video thumbnails preserve their 16:9 framing.
follow-best-practices `browser-platform-hygiene`	issues	high	Lighthouse reported missing source maps, DevTools inspector issues, and one BFCache restoration failure. F13 medium: Production platform hygiene has BFCache, source-map, and DevTools Issues failures.
be-discoverable `title-and-description`	pass	high	Home has title YouTube and a descriptive meta description; search has a query-specific title; watch has a content-specific title and description.
be-discoverable `crawlable-and-mobile-friendly`	issues	high	Rendered search links use real watch hrefs and viewport metadata is present, but discoverability found only 5–6% rendered-word coverage without JavaScript and classified home/watch as JS shells. F14 high: Useful browse and watch content is largely absent for non-JavaScript crawlers.
be-discoverable `canonical-and-indexing-signals`	pass	high	The watch page returned 200 and exposed canonical https://www.youtube.com/watch?v=uT7MVcCQ4rw without a noindex signal.
be-discoverable `structured-and-shareable-metadata`	pass	high	The watch page exposed two JSON-LD blocks and complete Open Graph video title, description, image dimensions, URL, and embed metadata matching visible content.
be-private-and-secure `secure-transport-and-headers`	issues	high	Headers showed HTTPS, HSTS, nosniff, X-Frame-Options, CSP and Trusted Types, but the CSP permits unsafe-inline/unsafe-eval and Referrer-Policy is absent. F15 medium: Strong baseline headers are weakened by CSP allowances and a missing Referrer-Policy.
be-private-and-secure `data-minimisation-and-third-parties`	issues	high	HAR attributed 108 of 144 requests to third-party origins; tracker scan found 9 third-party origins (87 font requests alone), while the consent copy states audience measurement occurs before optional personalization. F16 medium: The pre-decision page makes a very large third-party request footprint.
be-private-and-secure `in-context-permissions-and-modern-auth`	pass	high	No geolocation, notification, camera, or microphone prompt appeared on load; authentication is delegated to accounts.google.com rather than an inline password form.
be-private-and-secure `defensive-browser-policies`	issues	high	HSTS, SAMEORIGIN, nosniff, Permissions-Policy and Trusted Types are present, but Referrer-Policy is missing and CSP retains unsafe-inline/unsafe-eval allowances. F15 medium: Strong baseline headers are weakened by CSP allowances and a missing Referrer-Policy.
be-resilient `progressive-enhancement`	issues	high	Discoverability measured only 6% raw/rendered word overlap on home and 5% on watch, classifying both as JavaScript shells; crawler screenshots omit the useful browse/watch content. F17 high: Core content depends on JavaScript despite large server responses.
be-resilient `resilient-runtime-behaviour`	pass	high	Consent, search filters, result cards, watch player and recovery state rendered without clipping at tested desktop/mobile sizes; invalid content produced a stable recovery UI.
be-resilient `offline-and-installable`	pass	medium	Runtime inspection found a linked manifest and an active service-worker controller, direct installability/offline infrastructure evidence (offline media playback was not claimed).
be-resilient `network-and-http-failure-states`	pass	high	The invalid-video route displayed a specific unavailable state and GO TO HOME recovery rather than a blank shell or infinite spinner.
be-internationalised `lang-dir-and-logical-properties`	pass	high	The document declares lang=en-GB and exposes a visible en-GB language control; mobile reflow preserved reading order.
be-internationalised `locale-aware-data`	pass	medium	Rendered counts and relative dates use localized compact forms such as 159k views, 2 months ago, and en-GB language selection.
be-internationalised `time-zone-correctness`	not-applicable	high	The anonymous representative paths expose relative ages rather than user-scheduled or cross-zone events; no time-zone-sensitive editing flow applied.
be-trustworthy `no-dark-patterns`	pass	high	Reject all and Accept all are adjacent, similarly sized dark buttons, More options is available, and the copy distinguishes necessary measurement from optional personalization.
be-trustworthy `humane-error-handling`	pass	high	The invalid-video state explains the problem in plain language and offers GO TO HOME; consent offers reject, accept, and more-options paths without a dead end.
be-trustworthy `trustworthy-input-assistance`	not-applicable	high	The anonymous representative paths contained search and consent controls but no address, payment, sign-in, or sign-up form owned by youtube.com.
be-trustworthy `safe-commercial-and-account-flows`	not-applicable	high	Premium purchase and authenticated account-management flows were explicitly outside this anonymous, no-purchase audit scope.
be-sustainable `optimised-assets`	issues	high	The initial consent/home load transferred 4.06MB, including 3.04MB JavaScript, despite showing little primary media content. F18 high: The anonymous consent state consumes an excessive network and third-party budget.
be-sustainable `no-wasteful-work`	issues	high	The consent/home HAR recorded 144 requests and 4.06MB before the user chose a consent option, including 98 fetch/XHR requests. F18 high: The anonymous consent state consumes an excessive network and third-party budget.
be-sustainable `third-party-and-media-budget`	issues	high	The HAR recorded 108 third-party requests and tracker inventory found 9 third-party origins; fonts.gstatic.com alone received 87 requests. F18 high: The anonymous consent state consumes an excessive network and third-party budget. F16 medium: The pre-decision page makes a very large third-party request footprint.
be-agent-ready `structured-agent-capabilities`	issues	high	Lighthouse agentic-browsing score was 0.33, failed accessibility-tree and llms.txt checks, while no WebMCP/agent tool declaration was observed. F19 high: The experience offers weak machine/agent access to its useful content and actions.
be-agent-ready `on-device-inference`	not-applicable	high	On-device language-model inference is not necessary to the core anonymous browse, search, and watch journeys.
be-memory-efficient `no-leak-under-repeated-interaction`	pass	high	After ten programmatic guide toggles, heap node count fell 1,406,303→1,405,700 and self size rose only 70,902,183→71,024,288 bytes (~0.17%), with HTMLElement count 1046→1045.
be-memory-efficient `bounded-footprint`	pass	medium	A loaded anonymous home/consent state used ~65.5MB JS heap and a 71.0MB heap snapshot; substantial but proportionate to a complex media SPA and stable across the repeated interaction.
be-memory-efficient `no-detached-dom-or-unbounded-listeners`	pass	high	The live DOM probe found zero disconnected queried elements, and post-interaction HTMLElement/closure/object counts did not grow.

Provenance

Canonical report: results/atomic/reports/0967-www_youtube_com.json
Report SHA-256: aa6f94521017102d33d4fbfb2b3f8d088e31e66691052197f23c50b12d574af5
Local retained report: runs/2026-07-17T17-27-24-856Z/atomic-reports/www_youtube_com/2026-07-24T04-59-54-077Z/report.json
Local evidence root: runs/2026-07-17T17-27-24-856Z/atomic-reports/www_youtube_com/2026-07-24T04-59-54-077Z
Catalog SHA-256: sha256:78ccfdb2d483f4c57d9dafed80fd86c6265585a56457c8dcfddc254b80fb44d7

Raw screenshots, HARs, traces, heaps, and other browser artifacts are retained at the local evidence root and intentionally are not committed. Artifact paths in the canonical report are relative to that root.