{ "url": "https://m.youtube.com", "auditedAt": "2026-07-21T07:39:01.000Z", "mode": "report", "status": "completed", "statusDetail": "Coverage-complete audit of the public first-time mobile entry, watch, search and error-route surfaces. Authenticated and post-consent playback/account journeys were not covered.", "page": { "appType": "hybrid", "framework": "YouTube custom elements / client-rendered application shell", "notes": "m.youtube.com redirects evidence sessions to www.youtube.com/?app=desktop while retaining a mobile viewport. A full-screen consent surface gates the underlying public application." }, "evidenceUsed": [ "screenshot", "DOM", "evaluate probes", "layout metrics", "DevTools trace", "HAR", "Lighthouse", "discoverability/no-JS comparison", "security headers", "cookies", "trackers", "secrets scan", "images audit", "heap summaries" ], "guidanceConsulted": [ "accessibility", "accessible-error-announcement", "adapt-scrollbar-to-contrast-preferences", "agentic-forms", "agentic-javascript-tools", "anchor-positioning-tab-underline", "animate-element-entry-exit", "animate-to-from-top-layer", "animate-to-intrinsic-sizes", "animated-select-picker", "apply-webgl-shaders", "autofill-address-form", "autofill-highlight-inputs", "autofill-payment-form", "autofill-sign-in-form", "autofill-sign-up-form", "batch-analytics-events", "brand-consistent-forms", "branded-select-styling", "break-up-long-tasks", "calculate-event-differentials", "calculate-total-foreground-time", "calculate-with-intrinsic-sizes", "capture-location-agnostic-data", "carousel-slide-effects", "carousel-snap-highlights", "child-state-based-styling", "complex-shapes", "component-specific-light-dark-theme", "conditional-async-dependencies", "consistent-cross-document-transitions", "content-based-styling", "coordinate-global-events", "cross-document-transitions", "css-layout", "css", "custom-select-picker-layouts", "customize-scrollbar-color-and-thickness", "dark-mode", "declarative-dialog-popover-control", "defer-rendering-heavy-content", "defer-work-until-scroll-ends", "deliver-optimized-decorative-images", "deprioritize-background-fetches", "design-token-reactivity", "detect-initial-visibility-state", "directional-navigation-transitions", "dynamic-sibling-animations", "dynamic-sibling-styling", "efficient-background-processing", "export-html-media-from-canvas", "expose-canvas-content-to-browser-features", "faster-spa-view-transitions", "flicker-free-client-side-ab-testing", "fluid-scaling", "form-fields-automatically-fit-contents", "format-human-readable-durations", "forms", "full-session-analytics", "group-element-transitions", "highlight-text-ranges", "html", "identify-heavy-scripts", "identify-inp-causes", "improve-next-page-load-performance", "improve-text-layout-and-legibility", "individual-transform-properties", "interactions-in-complex-layouts", "interactive-content-in-3d-scenes", "interactive-content-reveal", "interest-triggered-action-previews", "interest-triggered-tooltips", "language-detection", "language-model", "light-dismiss-a-dialog", "manage-recurring-intervals", "model-partial-time-concepts", "move-dom-element-without-losing-state", "navigation-drawer", "optimize-image-priority", "optimize-preload-priority", "optimize-script-priority", "overflow-clipping-control", "parallax-scroll-effects", "passkey-authentication", "passkey-conditional-create", "passkey-management", "passkey-reauthentication", "passkey-registration", "passkeys", "performance", "persistent-app-tours", "persistent-toast-notifications", "persistent-top-layer-ui", "physics-based-easing", "platform-controls-dismiss-dialog", "position-aware-tooltips", "precise-text-alignment", "prevent-text-wrapping", "privacy", "pull-to-reveal", "reduce-style-repetition", "required-field-feedback", "resilient-context-menus-and-nested-dropdowns", "resolution-optimized-pseudo-elements", "rich-media-picker", "same-document-transitions", "schedule-tasks-by-priority", "scroll-entry-exit-effects", "scroll-position-aware-elements", "scroll-progress-indicator", "scroll-snap-realtime-feedback", "scroll-snap-state-sync", "scroll-target-on-load", "scrollability-affordance-hints", "scrollytelling", "search-hidden-content", "security", "select-menu-interaction", "sequence-distributed-events", "shaped-cutouts", "shrinking-header-on-scroll", "size-aware-styling", "soft-edge-content-fade", "stabilize-reactive-state", "stack-drill-down", "style-parent-with-has", "summarizer", "support-global-calendar-systems", "swipe-to-remove", "translator", "validate-input-after-interaction", "visually-stable-font-fallbacks", "visually-stable-mixed-fonts", "visually-texture-content", "webmcp" ], "artifacts": [ { "type": "screenshot", "path": "evidence/home-mobile.png", "caption": "First-viewport mobile consent surface", "condition": "viewport 390x844", "findingIds": [ "F02" ] }, { "type": "screenshot", "path": "evidence/home-desktop.png", "caption": "Desktop consent surface", "condition": "viewport 1440x900", "findingIds": [] }, { "type": "screenshot", "path": "evidence/home-dark-reduced.png", "caption": "Consent surface under dark and reduced-motion preferences", "condition": "prefers-color-scheme: dark; prefers-reduced-motion: reduce", "findingIds": [ "F01" ] }, { "type": "screenshot", "path": "evidence/home-high-contrast.png", "caption": "Consent surface with increased contrast preference", "condition": "prefers-contrast: more", "findingIds": [] }, { "type": "screenshot", "path": "evidence/watch-mobile.png", "caption": "Watch template first-time mobile surface", "condition": "viewport 390x844", "findingIds": [ "F02" ] }, { "type": "screenshot", "path": "evidence/search-mobile.png", "caption": "Search template first-time mobile surface", "condition": "viewport 390x844", "findingIds": [ "F02" ] }, { "type": "screenshot", "path": "evidence/error-route-mobile.png", "caption": "Unknown-route first-time mobile surface", "condition": "viewport 390x844", "findingIds": [ "F02" ] }, { "type": "layout", "path": "evidence/home-layout.json", "caption": "Mobile overflow, CLS and long-task observations", "condition": "viewport 390x844", "findingIds": [ "F04" ] }, { "type": "trace", "path": "evidence/home-trace", "caption": "DevTools performance trace", "condition": "mobile load", "findingIds": [] }, { "type": "trace-summary", "path": "evidence/home-trace-summary.json", "caption": "Compact trace timings and long tasks", "condition": "mobile load", "findingIds": [ "F03", "F04" ] }, { "type": "har", "path": "evidence/home.har", "caption": "Network archive", "condition": "mobile load", "findingIds": [ "F05", "F14", "F16" ] }, { "type": "har-summary", "path": "evidence/home-summary.json", "caption": "Network totals, origins and delivery signals", "condition": "mobile load", "findingIds": [ "F05", "F14", "F16" ] }, { "type": "lighthouse", "path": "evidence/lighthouse.json", "caption": "Lighthouse audit JSON", "condition": "mobile simulated load", "findingIds": [] }, { "type": "other", "path": "evidence/lighthouse-summary.json", "caption": "Compact Lighthouse scores and failed audits", "condition": "mobile simulated load", "findingIds": [ "F03", "F05", "F06", "F07", "F08", "F09", "F10", "F16" ] }, { "type": "other", "path": "evidence/lighthouse-details.json", "caption": "Selected Lighthouse failure details", "condition": "mobile simulated load", "findingIds": [ "F06", "F07", "F08", "F09", "F10" ] }, { "type": "discoverability", "path": "evidence/home-discoverability.json", "caption": "Home raw/rendered content comparison", "condition": "no-JavaScript crawler", "findingIds": [ "F11" ] }, { "type": "screenshot", "path": "evidence/home-discoverability-rendered.png", "caption": "Home browser view", "condition": "JavaScript enabled", "findingIds": [ "F11" ] }, { "type": "screenshot", "path": "evidence/home-discoverability-crawler.png", "caption": "Home crawler view", "condition": "JavaScript disabled", "findingIds": [ "F11" ] }, { "type": "discoverability", "path": "evidence/watch-discoverability.json", "caption": "Watch raw/rendered content comparison", "condition": "no-JavaScript crawler", "findingIds": [ "F11", "F13" ] }, { "type": "screenshot", "path": "evidence/watch-discoverability-rendered.png", "caption": "Watch browser view", "condition": "JavaScript enabled", "findingIds": [ "F11", "F13" ] }, { "type": "screenshot", "path": "evidence/watch-discoverability-crawler.png", "caption": "Watch crawler view", "condition": "JavaScript disabled", "findingIds": [ "F11", "F13" ] }, { "type": "heap", "path": "evidence/heap-baseline", "caption": "Baseline readable heap summary", "condition": "before repeated scroll", "findingIds": [] }, { "type": "heap", "path": "evidence/heap-post-scroll", "caption": "Post-interaction readable heap summary", "condition": "after ten scroll cycles", "findingIds": [] }, { "type": "other", "path": "evidence/headers.json", "caption": "Security response headers", "condition": "initial load", "findingIds": [ "F12" ] }, { "type": "other", "path": "evidence/cookies.json", "caption": "Cookie flags and duration", "condition": "initial load", "findingIds": [ "F12" ] }, { "type": "other", "path": "evidence/trackers.json", "caption": "Third-party origin/tracker inventory", "condition": "initial load", "findingIds": [] }, { "type": "other", "path": "evidence/secrets.json", "caption": "Client secret-pattern scan", "condition": "initial load", "findingIds": [] }, { "type": "other", "path": "evidence/images.json", "caption": "Rendered image diagnostics", "condition": "initial load", "findingIds": [] }, { "type": "other", "path": "evidence/focus-target-probe.json", "caption": "Focus visibility and target dimensions", "condition": "keyboard/programmatic focus", "findingIds": [ "F08", "F15" ] }, { "type": "other", "path": "evidence/watch-metadata.json", "caption": "Watch page title, canonical, OG and JSON-LD metadata", "condition": "watch template", "findingIds": [] }, { "type": "other", "path": "evidence/preferences-probe.json", "caption": "Reduced-motion animation probe", "condition": "prefers-reduced-motion: reduce", "findingIds": [] }, { "type": "dom", "path": "evidence/home-dom.json", "caption": "Entry-page DOM evidence", "condition": "mobile load", "findingIds": [] }, { "type": "other", "path": "evidence/robots.json", "caption": "robots.txt contents", "condition": "crawler fetch", "findingIds": [] }, { "type": "other", "path": "evidence/sitemap.json", "caption": "sitemap endpoint response", "condition": "crawler fetch", "findingIds": [] } ], "config": { "loaded": false }, "coverage": { "catalogVersion": "modern-web-guidance@0.0.172", "catalogChecksum": "sha256:78ccfdb2d483f4c57d9dafed80fd86c6265585a56457c8dcfddc254b80fb44d7", "expected": 58, "recorded": 58, "judged": 58, "blocked": 0, "notRun": 0, "missing": 0, "unknown": 0, "duplicates": 0, "complete": true }, "checkOutcomes": [ { "principleId": "respect-user-preferences", "checkId": "respects-color-scheme", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "The prefers-color-scheme:dark screenshot is pixel-identical in appearance and file size (96,160 bytes) to the light capture, remaining a bright white full-screen surface even though matchMedia reports dark=true.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-dark-reduced.png" ], "findingIds": [ "F01" ] }, { "principleId": "respect-user-preferences", "checkId": "respects-reduced-motion", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Preference probe reports reduced=true and zero active animations on the consent surface.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-dark-reduced.png" ] }, { "principleId": "respect-user-preferences", "checkId": "respects-contrast", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "High-contrast screenshot preserves readable text, icons, borders, and controls without clipping.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-high-contrast.png" ] }, { "principleId": "implement-natural-interactions", "checkId": "view-transitions", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The audited initial consent state does not perform an abrupt in-document state swap; navigation uses normal document navigation.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "implement-natural-interactions", "checkId": "scroll-driven-animations", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No scroll-linked storytelling, parallax, carousel motion, or entry/exit reveal is present on the audited consent surface.", "reason": "No scroll-linked storytelling, parallax, carousel motion, or entry/exit reveal is present on the audited consent surface." }, { "principleId": "implement-natural-interactions", "checkId": "physical-gestures", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No gesture-driven removal, pull-to-refresh replacement, or custom swipe interaction is exposed on the audited surface.", "reason": "No gesture-driven removal, pull-to-refresh replacement, or custom swipe interaction is exposed on the audited surface." }, { "principleId": "provide-guided-navigation", "checkId": "scroll-state-aware-chrome", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The consent document scrolls within a stable single-column surface without JS-driven sticky chrome obscuring content.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "provide-guided-navigation", "checkId": "anchored-positioning", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No tooltip, popover, or edge-positioned menu is opened on the consent path.", "reason": "No tooltip, popover, or edge-positioned menu is opened on the consent path." }, { "principleId": "provide-guided-navigation", "checkId": "directs-attention", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Heading, explanatory sequence, icon bullets, and equal decision controls provide a clear reading and decision order.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "maximize-content-reduce-noise", "checkId": "no-intrusive-interruptions", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Mobile screenshots on home, search, watch, and an error route show only the consent document; Reject all and Accept all are below the initial 844px viewport after several paragraphs.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png", "evidence/watch-mobile.png", "evidence/search-mobile.png", "evidence/error-route-mobile.png" ], "findingIds": [ "F02" ] }, { "principleId": "maximize-content-reduce-noise", "checkId": "semantic-dismissible-primitives", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The consent surface is exposed as a modal/dialog-like custom element, traps focus, and provides explicit Reject, Accept, and More options actions.", "pathIds": [ "home" ], "artifacts": [ "evidence/focus-target-probe.json" ] }, { "principleId": "maximize-content-reduce-noise", "checkId": "reduced-chrome", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The screenshot shows a restrained single-column consent layout with little decorative application chrome.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "adapt-to-the-form-factor", "checkId": "responsive-no-horizontal-scroll", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Layout at 390×844 reports scrollWidth=clientWidth=390 and horizontalOverflowPx=0 with viewport meta present.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-layout.json" ] }, { "principleId": "adapt-to-the-form-factor", "checkId": "component-level-responsiveness", "status": "pass", "confidence": "medium", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Mobile and desktop captures reflow the consent layout to the available viewport without fixed desktop-width overflow.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png", "evidence/home-desktop.png" ] }, { "principleId": "adapt-to-the-form-factor", "checkId": "input-modality-aware", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "The target probe measured Guide, Search, Settings and icon controls at 24×24 CSS px, below the recommended 44×44 mobile target, although consent decision buttons are 40px high and keyboard focus remains visible.", "pathIds": [ "home" ], "artifacts": [ "evidence/focus-target-probe.json" ], "findingIds": [ "F15" ] }, { "principleId": "support-core-task-success", "checkId": "clear-purpose-and-primary-action", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The heading states “Before you continue to YouTube” and the copy explicitly explains Reject all, Accept all, and More options.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "support-core-task-success", "checkId": "primary-flow-completion", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The consent surface exposes equally labelled Reject all and Accept all completion actions plus More options, without hidden required fields.", "pathIds": [ "home" ], "artifacts": [ "evidence/focus-target-probe.json" ] }, { "principleId": "support-core-task-success", "checkId": "clear-system-state-and-recovery", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The modal clearly states why content is paused and offers rejection, acceptance, settings, privacy, terms, and sign-in paths.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "be-fast-and-stable", "checkId": "good-core-web-vitals", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse measured FCP 4.9s, LCP 6.7s, TBT 256ms and performance 0.59; the independent trace measured LCP 3.94s and 286ms total blocking time.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/home-trace-summary.json" ], "findingIds": [ "F03" ] }, { "principleId": "be-fast-and-stable", "checkId": "visual-stability", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Layout observer measured CLS 0.000143 and Lighthouse measured 0.000714, both well inside the good threshold.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-layout.json", "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ] }, { "principleId": "be-fast-and-stable", "checkId": "efficient-main-thread", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "The trace recorded five long tasks, including 267ms, with 285.88ms total blocking time; layout observation independently found a 413ms task.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-trace-summary.json", "evidence/home-layout.json" ], "findingIds": [ "F04" ] }, { "principleId": "be-fast-and-stable", "checkId": "efficient-resource-delivery", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse flagged render-blocking requests with an estimated 210ms saving and a long network dependency tree; HAR transferred 4.05MB over 146 requests before consent completion.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-summary.json", "evidence/home.har", "evidence/lighthouse-summary.json" ], "findingIds": [ "F16" ] }, { "principleId": "be-fast-and-stable", "checkId": "trim-unused-and-duplicate-code", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "HAR captured 146 requests and 4,047,594 transferred bytes, including 3,031,432 script bytes. Lighthouse estimated 639KiB unused JavaScript and 153KiB unused CSS.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-summary.json", "evidence/home.har", "evidence/lighthouse-summary.json" ], "findingIds": [ "F05" ] }, { "principleId": "be-inclusive", "checkId": "names-roles-labels", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse accessibility 0.85 found the visible “en-GB” button name does not match aria-label “Language: English (United Kingdom)”, and the underlying language select has no label or accessible name.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "findingIds": [ "F06" ] }, { "principleId": "be-inclusive", "checkId": "sufficient-contrast", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse measured the Search YouTube text at 3.06:1 (#717171 on #272727), below the required 4.5:1 for 16px normal text; links in text also rely on colour alone.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "findingIds": [ "F07" ] }, { "principleId": "be-inclusive", "checkId": "structure-and-focus", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Consent surface has a clear heading and keyboard focus-visible styles; Lighthouse did not flag focus order or landmark failures.", "pathIds": [ "home" ], "artifacts": [ "evidence/focus-target-probe.json", "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ] }, { "principleId": "be-inclusive", "checkId": "legible-text", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Mobile screenshot shows comfortable 16px body text, adequate line spacing, and no clipped wrapping at 390px.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "be-inclusive", "checkId": "zoom-reflow-targets-and-media", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse found user-scalable=no / a restrictive maximum-scale in the viewport meta. The focus/target probe also measured several header controls at only 24×24 CSS px.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json", "evidence/focus-target-probe.json" ], "findingIds": [ "F08" ] }, { "principleId": "follow-best-practices", "checkId": "no-console-errors", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse captured an HTTP 400 from /youtubei/v1/feedback?prettyPrint=false and scored the console-errors audit 0.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "findingIds": [ "F09" ] }, { "principleId": "follow-best-practices", "checkId": "sound-document-and-assets", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Lighthouse passes doctype, charset, image aspect ratio, and deprecated API audits.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ] }, { "principleId": "follow-best-practices", "checkId": "browser-platform-hygiene", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Lighthouse found missing source maps for large first-party JavaScript, Inspector issues, and a BFCache failure caused by cache-control:no-store plus an HTTP-only cookie mutation.", "pathIds": [ "home" ], "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "findingIds": [ "F10" ] }, { "principleId": "be-discoverable", "checkId": "title-and-description", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Home has title YouTube and a meta description; the watch page has a unique descriptive title and description.", "pathIds": [ "watch" ], "artifacts": [ "evidence/watch-metadata.json" ] }, { "principleId": "be-discoverable", "checkId": "crawlable-and-mobile-friendly", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Discoverability captures classified both home and watch as JavaScript shells with only 6% rendered-word coverage in raw HTML. The crawler screenshots show skeleton cards rather than the rendered labels and page content.", "pathIds": [ "watch" ], "artifacts": [ "evidence/home-discoverability.json", "evidence/home-discoverability-rendered.png", "evidence/home-discoverability-crawler.png", "evidence/watch-discoverability.json", "evidence/watch-discoverability-rendered.png", "evidence/watch-discoverability-crawler.png" ], "findingIds": [ "F11" ] }, { "principleId": "be-discoverable", "checkId": "canonical-and-indexing-signals", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Watch response is HTTP 200 with canonical https://www.youtube.com/watch?v=uT7MVcCQ4rw; robots.txt is available and does not block watch URLs.", "pathIds": [ "watch" ], "artifacts": [ "evidence/watch-metadata.json", "evidence/robots.json" ] }, { "principleId": "be-discoverable", "checkId": "structured-and-shareable-metadata", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Watch page exposes canonical metadata, 18 Open Graph entries and two JSON-LD blocks that match the visible video title and thumbnail.", "pathIds": [ "watch" ], "artifacts": [ "evidence/watch-metadata.json" ] }, { "principleId": "be-private-and-secure", "checkId": "secure-transport-and-headers", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "HTTPS, HSTS, nosniff, SAMEORIGIN, CSP and Secure cookies are present; no mixed-content or sensitive-secret signal was found.", "pathIds": [ "home" ], "artifacts": [ "evidence/headers.json", "evidence/cookies.json", "evidence/secrets.json" ] }, { "principleId": "be-private-and-secure", "checkId": "data-minimisation-and-third-parties", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Tracker primitive found no known tracker domains before consent; SameSite cookies are first-party and public Google API keys are expected client configuration, not secrets.", "pathIds": [ "home" ], "artifacts": [ "evidence/trackers.json", "evidence/cookies.json", "evidence/secrets.json" ] }, { "principleId": "be-private-and-secure", "checkId": "in-context-permissions-and-modern-auth", "status": "pass", "confidence": "medium", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "No geolocation/notification permission prompt occurs on load; a sign-in action is user initiated. Authentication internals were not required to judge prompt timing on this path.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "be-private-and-secure", "checkId": "defensive-browser-policies", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Headers include HSTS, nosniff, SAMEORIGIN and Trusted Types, but CSP still permits unsafe-eval/unsafe-inline and Referrer-Policy is absent.", "pathIds": [ "home" ], "artifacts": [ "evidence/headers.json", "evidence/cookies.json" ], "findingIds": [ "F12" ] }, { "principleId": "be-resilient", "checkId": "progressive-enhancement", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "Raw HTML comparison found only 6% content-word coverage on the watch page; the no-JavaScript screenshot is largely a skeleton despite the server response containing title metadata.", "pathIds": [ "watch" ], "artifacts": [ "evidence/watch-discoverability.json", "evidence/watch-discoverability-rendered.png", "evidence/watch-discoverability-crawler.png" ], "findingIds": [ "F13" ] }, { "principleId": "be-resilient", "checkId": "resilient-runtime-behaviour", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "The consent overlay remains within the viewport, scrolls without horizontal clipping, preserves controls, and presents stable state.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-layout.json" ] }, { "principleId": "be-resilient", "checkId": "offline-and-installable", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "YouTube playback and search are intrinsically network-dependent; an install/offline playback promise was not part of the unauthenticated web surface audited.", "reason": "YouTube playback and search are intrinsically network-dependent; an install/offline playback promise was not part of the unauthenticated web surface audited." }, { "principleId": "be-resilient", "checkId": "network-and-http-failure-states", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "A nonexistent route still renders a stable recoverable consent entry rather than a blank screen; users retain navigation/sign-in/privacy controls.", "pathIds": [ "home" ], "artifacts": [ "evidence/error-route-mobile.png" ] }, { "principleId": "be-internationalised", "checkId": "lang-dir-and-logical-properties", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "html lang is en-GB and a prominent language picker offers many locales; the mobile layout preserves reading order.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-dom.json", "evidence/home-mobile.png" ] }, { "principleId": "be-internationalised", "checkId": "locale-aware-data", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "The audited consent surface exposes no dates, numbers, currencies, durations, or calendars requiring locale formatting.", "reason": "The audited consent surface exposes no dates, numbers, currencies, durations, or calendars requiring locale formatting." }, { "principleId": "be-internationalised", "checkId": "time-zone-correctness", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "The audited surface exposes no scheduled or time-zone-sensitive event data.", "reason": "The audited surface exposes no scheduled or time-zone-sensitive event data." }, { "principleId": "be-trustworthy", "checkId": "no-dark-patterns", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Reject all and Accept all use equal button treatment and More options is explicit; no preselected checkbox, confirmshaming, or disguised advert appears.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-mobile.png" ] }, { "principleId": "be-trustworthy", "checkId": "humane-error-handling", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No editable form or validation flow appears on the audited unauthenticated consent surface.", "reason": "No editable form or validation flow appears on the audited unauthenticated consent surface." }, { "principleId": "be-trustworthy", "checkId": "trustworthy-input-assistance", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No address, payment, sign-in, sign-up, or other editable input appears on the audited consent surface.", "reason": "No address, payment, sign-in, sign-up, or other editable input appears on the audited consent surface." }, { "principleId": "be-trustworthy", "checkId": "safe-commercial-and-account-flows", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No checkout, subscription, authenticated account-management, or sensitive-action flow was entered; the visible consent choice was assessed under no-dark-patterns.", "reason": "No checkout, subscription, authenticated account-management, or sensitive-action flow was entered; the visible consent choice was assessed under no-dark-patterns." }, { "principleId": "be-sustainable", "checkId": "optimised-assets", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Images primitive found no oversized or legacy raster payload on the consent path; HAR image transfer was only 127 bytes.", "pathIds": [ "home" ], "artifacts": [ "evidence/images.json", "evidence/home-summary.json", "evidence/home.har" ] }, { "principleId": "be-sustainable", "checkId": "no-wasteful-work", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "No ongoing animation is active under reduced motion; repeated scrolling did not grow heap, though pre-consent request volume is separately flagged.", "pathIds": [ "home" ], "artifacts": [ "evidence/preferences-probe.json", "evidence/heap-baseline", "evidence/heap-post-scroll" ] }, { "principleId": "be-sustainable", "checkId": "third-party-and-media-budget", "status": "issues", "confidence": "high", "method": "Direct multimodal evidence matched to the check outcome.", "evidence": "The first-load HAR transferred 4.05MB across 146 requests before content access, including 3.03MB script and 100 XHR/fetch requests. Host classification overstates third parties because m.youtube.com redirects to www.youtube.com, but the total work remains large.", "pathIds": [ "home" ], "artifacts": [ "evidence/home-summary.json", "evidence/home.har" ], "findingIds": [ "F14" ] }, { "principleId": "be-agent-ready", "checkId": "structured-agent-capabilities", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "The public watch/content surface provides metadata but exposes no safe transactional capability that requires WebMCP tools; emerging agent actions are out of this run’s scope.", "reason": "The public watch/content surface provides metadata but exposes no safe transactional capability that requires WebMCP tools; emerging agent actions are out of this run’s scope." }, { "principleId": "be-agent-ready", "checkId": "on-device-inference", "status": "not-applicable", "confidence": "high", "method": "Applicability judgement from recon and the available UI surface.", "evidence": "No summarisation or language-model task is offered in the audited unauthenticated surface, so on-device inference has no applicable user-facing task.", "reason": "No summarisation or language-model task is offered in the audited unauthenticated surface, so on-device inference has no applicable user-facing task." }, { "principleId": "be-memory-efficient", "checkId": "no-leak-under-repeated-interaction", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "After ten top-to-bottom scroll cycles, retained self size fell from 70,528,211 to 70,480,731 bytes; node count changed by only 2,143 (0.15%).", "pathIds": [ "home" ], "artifacts": [ "evidence/heap-baseline", "evidence/heap-post-scroll" ] }, { "principleId": "be-memory-efficient", "checkId": "bounded-footprint", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Heap summary reports about 70.5MB retained self size for the loaded YouTube consent/application shell; high but bounded for this media application.", "pathIds": [ "home" ], "artifacts": [ "evidence/heap-baseline", "evidence/heap-post-scroll" ] }, { "principleId": "be-memory-efficient", "checkId": "no-detached-dom-or-unbounded-listeners", "status": "pass", "confidence": "high", "method": "Active visual/objective inspection using the referenced artifacts.", "evidence": "Neither heap summary contains Detached* constructors and the repeated-scroll comparison shows no unbounded retained growth.", "pathIds": [ "home" ], "artifacts": [ "evidence/heap-baseline", "evidence/heap-post-scroll" ] } ], "principleOutcomes": [ { "principleId": "respect-user-preferences", "expectation": "default", "status": "issues", "findingIds": [ "F01" ] }, { "principleId": "implement-natural-interactions", "expectation": "default", "status": "pass" }, { "principleId": "provide-guided-navigation", "expectation": "default", "status": "pass" }, { "principleId": "maximize-content-reduce-noise", "expectation": "default", "status": "issues", "findingIds": [ "F02" ] }, { "principleId": "adapt-to-the-form-factor", "expectation": "default", "status": "issues", "findingIds": [ "F15" ] }, { "principleId": "support-core-task-success", "expectation": "default", "status": "pass" }, { "principleId": "be-fast-and-stable", "expectation": "default", "status": "issues", "findingIds": [ "F03", "F04", "F16", "F05" ] }, { "principleId": "be-inclusive", "expectation": "default", "status": "issues", "findingIds": [ "F06", "F07", "F08" ] }, { "principleId": "follow-best-practices", "expectation": "default", "status": "issues", "findingIds": [ "F09", "F10" ] }, { "principleId": "be-discoverable", "expectation": "default", "status": "issues", "findingIds": [ "F11" ] }, { "principleId": "be-private-and-secure", "expectation": "default", "status": "issues", "findingIds": [ "F12" ] }, { "principleId": "be-resilient", "expectation": "contextual", "status": "issues", "findingIds": [ "F13" ] }, { "principleId": "be-internationalised", "expectation": "contextual", "status": "pass" }, { "principleId": "be-trustworthy", "expectation": "default", "status": "pass" }, { "principleId": "be-sustainable", "expectation": "contextual", "status": "issues", "findingIds": [ "F14" ] }, { "principleId": "be-agent-ready", "expectation": "contextual", "status": "not-applicable", "reason": "The public watch/content surface provides metadata but exposes no safe transactional capability that requires WebMCP tools; emerging agent actions are out of this run’s scope. No summarisation or language-model task is offered in the audited unauthenticated surface, so on-device inference has no applicable user-facing task." }, { "principleId": "be-memory-efficient", "expectation": "default", "status": "pass" } ], "paths": [ { "id": "home", "description": "Public first-time mobile entry and consent journey; represents global shell, preferences, responsiveness, privacy and startup performance.", "url": "https://m.youtube.com", "conditions": [ "viewport 390x844", "viewport 1440x900", "prefers-color-scheme: dark", "prefers-reduced-motion: reduce", "prefers-contrast: more", "keyboard/programmatic focus", "JavaScript disabled crawler" ], "result": "issues" }, { "id": "watch", "description": "Representative video detail/watch template using a known public video; covers metadata, content rendering and crawler parity.", "url": "https://m.youtube.com/watch?v=uT7MVcCQ4rw", "conditions": [ "viewport 390x844", "JavaScript disabled crawler" ], "result": "issues" }, { "id": "search", "description": "Representative search/listing route; confirms the first-time gate and route-level experience.", "url": "https://m.youtube.com/results?search_query=modern+web+ui", "conditions": [ "viewport 390x844" ], "result": "issues" }, { "id": "error-route", "description": "Unknown route used to inspect resilient failure-state handling for a first-time visitor.", "url": "https://m.youtube.com/this-path-should-not-exist-web-uplift", "conditions": [ "viewport 390x844" ], "result": "pass" } ], "findings": [ { "id": "F01", "severity": "high", "confidence": "high", "principleId": "respect-user-preferences", "principleCheckId": "respects-color-scheme", "guidanceId": "dark-mode", "guidanceCategory": "user-experience", "pathId": "home", "url": "https://m.youtube.com", "summary": "The mandatory consent surface ignores the user’s dark colour preference.", "evidence": "The prefers-color-scheme:dark screenshot is pixel-identical in appearance and file size (96,160 bytes) to the light capture, remaining a bright white full-screen surface even though matchMedia reports dark=true.", "artifacts": [ "evidence/home-dark-reduced.png" ], "suggestedFix": "Apply color-scheme: light dark to the consent experience and derive surface, text, border, icon, and link colours from system-aware tokens or light-dark().", "effort": "medium" }, { "id": "F02", "severity": "high", "confidence": "high", "principleId": "maximize-content-reduce-noise", "principleCheckId": "no-intrusive-interruptions", "guidanceId": "light-dismiss-a-dialog", "guidanceCategory": "user-experience", "pathId": "home", "url": "https://m.youtube.com", "summary": "A long, full-viewport consent interstitial hides all YouTube content before first use.", "evidence": "Mobile screenshots on home, search, watch, and an error route show only the consent document; Reject all and Accept all are below the initial 844px viewport after several paragraphs.", "artifacts": [ "evidence/home-mobile.png", "evidence/watch-mobile.png", "evidence/search-mobile.png", "evidence/error-route-mobile.png" ], "suggestedFix": "Reduce the consent copy to the decision-critical summary in the first viewport, keep Reject all and Accept all equally prominent and immediately reachable, and put details behind an accessible disclosure.", "effort": "medium" }, { "id": "F03", "severity": "high", "confidence": "high", "principleId": "be-fast-and-stable", "principleCheckId": "good-core-web-vitals", "guidanceId": "performance", "guidanceCategory": "performance", "pathId": "home", "url": "https://m.youtube.com", "summary": "The first-time mobile experience paints too slowly.", "evidence": "Lighthouse measured FCP 4.9s, LCP 6.7s, TBT 256ms and performance 0.59; the independent trace measured LCP 3.94s and 286ms total blocking time.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/home-trace-summary.json" ], "suggestedFix": "Prioritise the consent surface’s LCP content, reduce startup JavaScript, defer nonessential work, and shorten critical request chains.", "effort": "large" }, { "id": "F04", "severity": "medium", "confidence": "high", "principleId": "be-fast-and-stable", "principleCheckId": "efficient-main-thread", "guidanceId": "break-up-long-tasks", "guidanceCategory": "performance", "pathId": "home", "url": "https://m.youtube.com", "summary": "Startup JavaScript blocks the main thread.", "evidence": "The trace recorded five long tasks, including 267ms, with 285.88ms total blocking time; layout observation independently found a 413ms task.", "artifacts": [ "evidence/home-trace-summary.json", "evidence/home-layout.json" ], "suggestedFix": "Break startup work into scheduler-prioritised tasks, defer below-the-fold application boot, and avoid hydrating content hidden by consent.", "effort": "large" }, { "id": "F05", "severity": "high", "confidence": "high", "principleId": "be-fast-and-stable", "principleCheckId": "trim-unused-and-duplicate-code", "guidanceId": "identify-heavy-scripts", "guidanceCategory": "performance", "pathId": "home", "url": "https://m.youtube.com", "summary": "The consent path ships a disproportionate application payload before the user can access content.", "evidence": "HAR captured 146 requests and 4,047,594 transferred bytes, including 3,031,432 script bytes. Lighthouse estimated 639KiB unused JavaScript and 153KiB unused CSS.", "artifacts": [ "evidence/home-summary.json", "evidence/home.har", "evidence/lighthouse-summary.json" ], "suggestedFix": "Serve a minimal consent entry bundle, split the full YouTube application behind the consent decision, remove duplicate/unused code, and defer media/feed requests.", "effort": "large" }, { "id": "F06", "severity": "high", "confidence": "high", "principleId": "be-inclusive", "principleCheckId": "names-roles-labels", "guidanceId": "accessibility", "guidanceCategory": "accessibility", "pathId": "home", "url": "https://m.youtube.com", "summary": "The consent language control has broken accessible naming.", "evidence": "Lighthouse accessibility 0.85 found the visible “en-GB” button name does not match aria-label “Language: English (United Kingdom)”, and the underlying language select has no label or accessible name.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "suggestedFix": "Give the language picker one consistent accessible name that includes its visible text, and associate a visible or programmatic label with the select.", "effort": "small" }, { "id": "F07", "severity": "high", "confidence": "high", "principleId": "be-inclusive", "principleCheckId": "sufficient-contrast", "guidanceId": "accessibility", "guidanceCategory": "accessibility", "pathId": "home", "url": "https://m.youtube.com", "summary": "Some primary UI text fails minimum colour contrast.", "evidence": "Lighthouse measured the Search YouTube text at 3.06:1 (#717171 on #272727), below the required 4.5:1 for 16px normal text; links in text also rely on colour alone.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "suggestedFix": "Increase foreground contrast to at least 4.5:1 and add a non-colour affordance such as underline for links embedded in prose.", "effort": "small" }, { "id": "F08", "severity": "high", "confidence": "high", "principleId": "be-inclusive", "principleCheckId": "zoom-reflow-targets-and-media", "guidanceId": "fluid-scaling", "guidanceCategory": "css", "pathId": "home", "url": "https://m.youtube.com", "summary": "The viewport configuration disables user zoom.", "evidence": "Lighthouse found user-scalable=no / a restrictive maximum-scale in the viewport meta. The focus/target probe also measured several header controls at only 24×24 CSS px.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json", "evidence/focus-target-probe.json" ], "suggestedFix": "Remove user-scalable=no and maximum-scale restrictions, and enlarge compact controls to a minimum 44×44 target while preserving the visible icon size.", "effort": "small" }, { "id": "F09", "severity": "medium", "confidence": "high", "principleId": "follow-best-practices", "principleCheckId": "no-console-errors", "guidanceId": "html", "guidanceCategory": "html", "pathId": "home", "url": "https://m.youtube.com", "summary": "The initial page load logs a failed application request.", "evidence": "Lighthouse captured an HTTP 400 from /youtubei/v1/feedback?prettyPrint=false and scored the console-errors audit 0.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "suggestedFix": "Do not send feedback until required state exists, validate the payload client-side, and handle expected rejection without emitting a console error.", "effort": "small" }, { "id": "F10", "severity": "medium", "confidence": "high", "principleId": "follow-best-practices", "principleCheckId": "browser-platform-hygiene", "guidanceId": "html", "guidanceCategory": "html", "pathId": "home", "url": "https://m.youtube.com", "summary": "The page misses platform diagnostics and navigation-restoration opportunities.", "evidence": "Lighthouse found missing source maps for large first-party JavaScript, Inspector issues, and a BFCache failure caused by cache-control:no-store plus an HTTP-only cookie mutation.", "artifacts": [ "evidence/lighthouse-summary.json", "evidence/lighthouse-details.json" ], "suggestedFix": "Publish production source maps to authorised diagnostics, resolve Inspector issues, and avoid no-store/cookie mutation on pages that can safely use BFCache.", "effort": "medium" }, { "id": "F11", "severity": "high", "confidence": "high", "principleId": "be-discoverable", "principleCheckId": "crawlable-and-mobile-friendly", "guidanceId": "html", "guidanceCategory": "html", "pathId": "watch", "url": "https://m.youtube.com/watch?v=uT7MVcCQ4rw", "summary": "Non-JavaScript crawlers receive only a small fraction of the visible content.", "evidence": "Discoverability captures classified both home and watch as JavaScript shells with only 6% rendered-word coverage in raw HTML. The crawler screenshots show skeleton cards rather than the rendered labels and page content.", "artifacts": [ "evidence/home-discoverability.json", "evidence/home-discoverability-rendered.png", "evidence/home-discoverability-crawler.png", "evidence/watch-discoverability.json", "evidence/watch-discoverability-rendered.png", "evidence/watch-discoverability-crawler.png" ], "suggestedFix": "Server-render meaningful feed and watch-page text, links, headings, and state so non-JavaScript crawlers receive the same core content rather than a skeleton shell.", "effort": "large" }, { "id": "F12", "severity": "medium", "confidence": "high", "principleId": "be-private-and-secure", "principleCheckId": "defensive-browser-policies", "guidanceId": "security", "guidanceCategory": "security", "pathId": "home", "url": "https://m.youtube.com", "summary": "The security policy has avoidable browser-defense gaps.", "evidence": "Headers include HSTS, nosniff, SAMEORIGIN and Trusted Types, but CSP still permits unsafe-eval/unsafe-inline and Referrer-Policy is absent.", "artifacts": [ "evidence/headers.json", "evidence/cookies.json" ], "suggestedFix": "Remove unsafe-eval and residual unsafe-inline dependencies from CSP, rely on nonces/strict-dynamic and Trusted Types, and set an explicit strict-origin-when-cross-origin or stricter Referrer-Policy.", "effort": "large" }, { "id": "F13", "severity": "high", "confidence": "high", "principleId": "be-resilient", "principleCheckId": "progressive-enhancement", "guidanceId": "stabilize-reactive-state", "guidanceCategory": "javascript", "pathId": "watch", "url": "https://m.youtube.com/watch?v=uT7MVcCQ4rw", "summary": "Core content is not progressively available without JavaScript.", "evidence": "Raw HTML comparison found only 6% content-word coverage on the watch page; the no-JavaScript screenshot is largely a skeleton despite the server response containing title metadata.", "artifacts": [ "evidence/watch-discoverability.json", "evidence/watch-discoverability-rendered.png", "evidence/watch-discoverability-crawler.png" ], "suggestedFix": "Render the watch title, channel, description, transcript affordance, and useful links in server HTML, then enhance playback and recommendations with JavaScript.", "effort": "large" }, { "id": "F14", "severity": "medium", "confidence": "high", "principleId": "be-sustainable", "principleCheckId": "third-party-and-media-budget", "guidanceId": "deprioritize-background-fetches", "guidanceCategory": "performance", "pathId": "home", "url": "https://m.youtube.com", "summary": "The pre-consent network and script budget is disproportionate to the visible consent task.", "evidence": "The first-load HAR transferred 4.05MB across 146 requests before content access, including 3.03MB script and 100 XHR/fetch requests. Host classification overstates third parties because m.youtube.com redirects to www.youtube.com, but the total work remains large.", "artifacts": [ "evidence/home-summary.json", "evidence/home.har" ], "suggestedFix": "Set a strict pre-consent budget, suppress media/feed fetching until needed, and defer low-priority background requests with visibility-aware scheduling.", "effort": "large" }, { "id": "F15", "severity": "medium", "confidence": "high", "principleId": "adapt-to-the-form-factor", "principleCheckId": "input-modality-aware", "guidanceId": "accessibility", "guidanceCategory": "accessibility", "pathId": "home", "url": "https://m.youtube.com", "summary": "Several mobile header controls expose undersized touch targets.", "evidence": "The target probe measured Guide, Search, Settings and icon controls at 24×24 CSS px, below the recommended 44×44 mobile target, although consent decision buttons are 40px high and keyboard focus remains visible.", "artifacts": [ "evidence/focus-target-probe.json" ], "suggestedFix": "Keep 24px icons but enlarge their interactive hit areas to at least 44×44 CSS px and retain visible focus styles.", "effort": "small" }, { "id": "F16", "severity": "high", "confidence": "high", "principleId": "be-fast-and-stable", "principleCheckId": "efficient-resource-delivery", "guidanceId": "optimize-script-priority", "guidanceCategory": "performance", "pathId": "home", "url": "https://m.youtube.com", "summary": "Critical delivery is burdened by render-blocking and oversized startup resources.", "evidence": "Lighthouse flagged render-blocking requests with an estimated 210ms saving and a long network dependency tree; HAR transferred 4.05MB over 146 requests before consent completion.", "artifacts": [ "evidence/home-summary.json", "evidence/home.har", "evidence/lighthouse-summary.json" ], "suggestedFix": "Inline only critical consent CSS, defer/module-load application scripts after the decision, preload only confirmed LCP resources, and shorten the startup dependency chain.", "effort": "large" } ], "taskList": [ { "id": "T01", "title": "Create a minimal, immediately actionable and preference-aware consent entry surface", "priority": 1, "findingIds": [ "F01", "F02", "F03", "F04", "F05", "F14", "F16" ], "guidanceId": "dark-mode", "status": "open" }, { "id": "T02", "title": "Server-render meaningful home and watch content for non-JavaScript consumers", "priority": 2, "findingIds": [ "F11", "F13" ], "guidanceId": "html", "status": "open" }, { "id": "T03", "title": "Fix consent/search accessibility: names, labels, contrast, zoom and target size", "priority": 3, "findingIds": [ "F06", "F07", "F08", "F15" ], "guidanceId": "accessibility", "status": "open" }, { "id": "T04", "title": "Tighten CSP and set an explicit Referrer-Policy", "priority": 4, "findingIds": [ "F12" ], "guidanceId": "security", "status": "open" }, { "id": "T05", "title": "Resolve feedback console failure, Inspector issues, source maps and BFCache blockers", "priority": 5, "findingIds": [ "F09", "F10" ], "guidanceId": "html", "status": "open" } ], "budget": { "pathCount": 4, "auditPasses": 1 }, "agent": "pi", "runId": "2026-07-21T07-34-49-272Z" }