# BeaverCheck Audit Report — https://yaml.org

**Date:** April 22, 2026  
**URL:** https://yaml.org  
**Overall Grade:** C (76/100)  
**Report:** https://beavercheck.com/results/8d24caa5-75a7-46a7-bb46-ef06acff5d70

## Top Findings

1. **[CRITICAL]** Content-Security-Policy header is missing — Security > Security Headers
2. **[CRITICAL]** HSTS header is missing — Security > Security Headers
3. **[CRITICAL]** No Content-Security-Policy header found — Security > Content Security Policy
4. **[CRITICAL]** 1 control(s) without accessible label — Accessibility > Form Accessibility
5. **[WARNING]** 7 third-party resources (81% of weight) — Performance > Page Weight Inventory

---

## Lighthouse Scores

| Category | Score |
|----------|-------|
| Performance | 80 |
| Accessibility | 93 |
| Best Practices | 96 |
| SEO | 100 |

---

## Security

### Security Headers (F — 10/100)

*2 of 10 headers properly configured*

- **[CRITICAL]** HSTS header is missing — Strict-Transport-Security forces browsers to use HTTPS, preventing downgrade attacks. Add the header with a max-age of at least 1 year.
- **[WARNING]** X-Content-Type-Options header is missing — This header prevents MIME-type sniffing, which can lead to XSS attacks. Set it to 'nosniff'.
- **[WARNING]** X-Frame-Options header is missing — This header prevents clickjacking by controlling who can embed your page in a frame. Set it to DENY or SAMEORIGIN.
- **[WARNING]** Referrer-Policy header is missing — Controls how much referrer information is sent with requests. Set to 'strict-origin-when-cross-origin' or stricter.
- **[WARNING]** Permissions-Policy header is missing — Controls which browser features (camera, microphone, geolocation) are allowed. Set it to restrict unused features.
- **[CRITICAL]** Content-Security-Policy header is missing — CSP is the most important header for preventing XSS attacks. See the CSP section for detailed analysis.
- **[WARNING]** Cross-Origin-Opener-Policy header is missing — COOP isolates your browsing context, preventing cross-origin side-channel attacks. Set to 'same-origin'.
- **[WARNING]** Cross-Origin-Embedder-Policy header is missing — COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.
- **[PASS]** X-Powered-By header is not present
- **[PASS]** Server header is present without version info

### Content Security Policy (F — 0/100)

*No enforcing CSP policy found*

- **[CRITICAL]** No Content-Security-Policy header found — CSP is the most effective defense against XSS attacks. Add a Content-Security-Policy header to restrict resource loading.

### TLS & Certificates (A+ — 100/100)

*TLS 1.3, 7 checks passed*

- **[PASS]** TLS 1.3 is used
- **[PASS]** Strong cipher suite is used
- **[INFO]** HTTP/2 is not negotiated — HTTP/2 provides multiplexing and header compression for better performance.
- **[PASS]** Certificate is valid (expires in 44 days)
- **[PASS]** Certificate chain has 2 certificates
- **[PASS]** Certificate uses modern signature algorithm
- **[PASS]** Certificate covers 1 domain(s)
- **[PASS]** Certificate is issued by a trusted CA

### Cookie Security (A+ — 100/100)

*No cookies set — no cookie security risks*

- **[PASS]** No cookies set — no cookie security risks

---

## Advanced Security

### Subresource Integrity (F — 20/100)

*0 of 3 external resources have SRI*

- **[WARNING]** External link from fonts.googleapis.com lacks integrity attribute — Without SRI, if this CDN is compromised, attackers could inject malicious code.
- **[WARNING]** External script from polyfill.io lacks integrity attribute — Without SRI, if this CDN is compromised, attackers could inject malicious code.
- **[WARNING]** External script from cdn.jsdelivr.net lacks integrity attribute — Without SRI, if this CDN is compromised, attackers could inject malicious code.

### JS Library Vulnerabilities (A+ — 100/100)

*No known vulnerabilities*

- **[PASS]** No known JavaScript library vulnerabilities detected

### Information Leakage (A+ — 100/100)

*No exposures*

- **[INFO]** No security.txt found — Consider adding a security.txt at /.well-known/security.txt.
- **[PASS]** No sensitive files exposed

### Email Security (F — 30/100)

*No DMARC*

- **[WARNING]** No DMARC record found — Without DMARC, email receivers have no policy for handling authentication failures.

### Permissions-Policy (D — 40/100)

*No header set*

- **[WARNING]** No Permissions-Policy header — Consider adding a Permissions-Policy header to restrict browser feature access from embedded content.

### CORS Configuration (C — 60/100)

*Origin: **

- **[INFO]** Access-Control-Allow-Origin: * — unrestricted — Any website can read this resource's response. Appropriate for public APIs but not for user-specific content.
- **[INFO]** Origin reflection not testable with a single request — Some servers reflect the request Origin header. This requires manual testing with a crafted Origin header.

---

## Performance

### Page Weight Budget (A+ — 100/100)

*404 KB transferred, 17 requests*

- **[PASS]** Page weighs 1.6 MB (404 KB transferred)
- **[PASS]** 17 HTTP requests
- **[INFO]** Estimated 0.08 g CO2 per page load

### Third-Party Impact (D — 50/100)

*81% third-party, 0 ms blocking*

- **[WARNING]** Third-party code accounts for 81% of page weight (326.1 KiB of 404.3 KiB)
- **[PASS]** Third-party blocking time is low (0 ms)

### Text Compression (A+ — 100/100)

*All text resources are compressed*

- **[PASS]** All text resources are compressed

### Image Optimization (A — 90/100)

*1 images, 0 KB saveable*

- **[WARNING]** https://yaml.org/assets/logo.png is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.

### JS Execution Cost (B — 80/100)

*798ms total JS execution*

- **[WARNING]** https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml...: 341ms CPU time
- **[WARNING]** https://yaml.org/assets/javascripts/bundle.50899de...: 253ms CPU time
- **[INFO]** https://yaml.org/: 102ms CPU time
- **[INFO]** Unattributable: 102ms CPU time
- **[WARNING]** Third-party scripts: 443ms (56% of total)

### Font Loading (A+ — 100/100)

*2 fonts (69 KB)*

- **[INFO]** 2 font(s) use font-display: swap (FOUT risk but functional)

### JS Bundles (B — 80/100)

*5 scripts, 122 KB unused*

- **[WARNING]** https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml...: 122 KB unused (49%) — Consider code splitting or tree shaking to reduce unused code.
- **[INFO]** Total unused JavaScript: 122 KB

### Resource Caching (A+ — 100/100)

*All resources properly cached*

- **[PASS]** No caching issues found

### Critical Rendering Path (A+ — 100/100)

*No render-blocking resources*

- **[PASS]** No render-blocking resources detected

### Resource Hints (A+ — 100/100)

*1 hints, 0 missing preconnects*

- **[PASS]** Page uses 1 resource hint(s)

### Page Weight Inventory (A — 85/100)

*17 resources · 404 KB · 122 KB savings available*

- **[PASS]** Within 1MB page-weight target
- **[INFO]** ~122 KB of savings available
- **[WARNING]** 7 third-party resources (81% of weight)
- **[INFO]** 1 resources over 200KB

### Render-Blocking Resources (A+ — 100/100)

*No render-blocking resources detected*

- **[PASS]** No render-blocking resources detected in <head>

### Third-Party Resources (A+ — 100/100)

*No third-party resources detected*


---

## Content Quality

### Links (A — 90/100)

*36 links checked, 34 healthy, 2 broken*

- **[WARNING]** 34 of 36 links are healthy
- **[WARNING]** Broken link: https://fonts.gstatic.com — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://polyfill.io/v3/polyfill.min.js?features=es6 — Found in <script src>. Get "https://polyfill.io/v3/polyfill.min.js?features=es6": resolve polyfill.io: lookup polyfill.io: no such host

### Mixed Content (A+ — 100/100)

*No mixed content detected — all resources use HTTPS.*

- **[PASS]** No mixed content detected — all resources use HTTPS

### Open Graph (F — 0/100)

*No Open Graph tags found — social sharing previews will be generic.*

- **[WARNING]** No Open Graph meta tags found — Without og:title, og:description, and og:image, social media platforms will generate a generic preview when your page is shared.

### Structured Data (C — 40/100)

*No structured data (JSON-LD) found.*

- **[INFO]** No structured data (JSON-LD) found — Adding structured data helps search engines understand your content and can enable rich results.

---

## Infrastructure

### DNS Records (A+ — 95/100)

*4 A records, 39 ms lookup*

- **[PASS]** Resolves to 4 IPv4 address(es)
- **[INFO]** No IPv6 (AAAA) records
- **[PASS]** 2 nameserver(s) configured
- **[INFO]** No MX records — email not configured via DNS
- **[INFO]** CAA records not checked — CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
- **[INFO]** No SPF record found in TXT records — SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.
- **[PASS]** DNS resolution time: 39 ms

### Redirect Chain (A+ — 100/100)

*No redirects — direct access*

- **[PASS]** No redirects — direct access

### IPv6 Readiness (C — 60/100)

*No IPv6 support*

- **[INFO]** No IPv6 (AAAA) records found — IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

### Crawlability (A — 90/100)

*no robots.txt, sitemap with 4 URLs*

- **[INFO]** No robots.txt found — robots.txt is optional but recommended. It tells search engine crawlers which pages to index.
- **[PASS]** sitemap.xml is present
- **[PASS]** sitemap.xml is valid XML
- **[PASS]** sitemap.xml contains 4 entries

### URL Variants (A+ — 100/100)

*www/non-www, trailing slash, HTTP→HTTPS*

- **[PASS]** www/non-www redirect configured correctly (preferred: non-www)
- **[PASS]** HTTP correctly 301-redirects to HTTPS

### Domain Intelligence (A+ — 100/100)

*yaml.org — via Gandi SAS, 25 years, 7 months old, hosted on Fastly*

- **[PASS]** Domain registered until Jan 5, 2031 (4 years, 9 months remaining)
- **[INFO]** DNSSEC is not enabled — DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.
- **[PASS]** Registrar: Gandi SAS
- **[WARNING]** Registrar lock is NOT enabled — The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.
- **[PASS]** Hosting: Fastly

---

## Compliance

### WCAG Compliance (A+ — 100/100)

*No testable criteria*


### Cookie Consent & Privacy (B — 80/100)

*No consent signals detected*

- **[WARNING]** No privacy policy link detected — A privacy policy page is recommended for transparency and may be legally required.
- **[INFO]** No terms of service link detected
- **[INFO]** No cookie consent banner detected
- **[INFO]** This is an automated check, not legal advice — BeaverCheck detects technical indicators of consent management. This does not constitute a legal compliance assessment. Consult a privacy professional for GDPR/CCPA compliance.

### Language & i18n (A — 90/100)

*Lang attribute present*

- **[PASS]** <html lang> attribute is present
- **[PASS]** <html lang> value is valid
- **[INFO]** No Content-Language HTTP header
- **[INFO]** Language signals are inconsistent — The <html lang> attribute and Content-Language header should agree.

### Readability & Typography (A+ — 100/100)

*Font sizes and tap targets checked*


### Viewport Configuration (A+ — 100/100)

*Viewport properly configured*

- **[PASS]** Viewport meta tag is present
- **[PASS]** width=device-width is set
- **[PASS]** User zooming is allowed

### Third-Party Trackers (A+ — 100/100)

*No third-party trackers detected*

- **[PASS]** No third-party trackers detected

---

## Legal

### Legal Page Ecosystem (F — 0/100)

*0 of 7 expected legal pages detected*

- **[WARNING]** Privacy Policy not detected — No link matching common Privacy Policy URL patterns or link text was found. Most websites are expected to have a Privacy Policy, especially those collecting user data.
- **[WARNING]** Terms of Service not detected — No link matching common Terms of Service URL patterns or link text was found. Most websites are expected to have a Terms of Service, especially those collecting user data.
- **[INFO]** Cookie Policy not detected — No link matching common Cookie Policy URL patterns or link text was found. Most websites are expected to have a Cookie Policy, especially those collecting user data.
- **[INFO]** Accessibility Statement not detected — No link matching common Accessibility Statement URL patterns or link text was found. Most websites are expected to have a Accessibility Statement, especially those collecting user data.
- **[INFO]** DMCA / Copyright Notice not detected — No link matching common DMCA / Copyright Notice URL patterns or link text was found. Most websites are expected to have a DMCA / Copyright Notice, especially those collecting user data.
- **[INFO]** Refund / Returns Policy not detected — No link matching common Refund / Returns Policy URL patterns or link text was found. Most websites are expected to have a Refund / Returns Policy, especially those collecting user data.
- **[INFO]** Acceptable Use Policy not detected — No link matching common Acceptable Use Policy URL patterns or link text was found. Most websites are expected to have a Acceptable Use Policy, especially those collecting user data.

### Copyright Notice (A+ — 100/100)

*© 2001-2026 YAML Made with Material for MkDocs ↑*

- **[PASS]** Copyright notice is up to date — Copyright notice is up to date: © 2001-2026 YAML Made with Material for MkDocs ↑
- **[PASS]** Copyright holder: YAML Made with Material for MkDocs ↑

### Regulatory Indicators

*0 regulatory indicator(s) detected*

- **[INFO]** This is a technical scan, not a legal assessment — BeaverCheck detects technical indicators that may suggest regulatory relevance. This is not a compliance audit and should not be relied upon for legal decisions. Consult qualified legal counsel for compliance assessments.
- **[INFO]** No specific regulatory indicators detected — No strong signals for GDPR, CCPA, ADA, PCI, HIPAA, or COPPA were found. This does not mean these regulations don't apply — it means we didn't detect common technical indicators.

### Third-Party Data Sharing

*0 third-party service(s) detected*

- **[INFO]** Data inventory for transparency purposes — This inventory identifies third-party services that receive data from your site visitors. Under regulations like GDPR (Article 30), maintaining records of data processing activities is commonly considered a best practice. This automated scan provides a starting point — it may not capture all data flows.
- **[INFO]** No recognized third-party data-sharing services detected — This page does not appear to load external tracking, analytics, or advertising scripts.

### Compliance Badges (C — 55/100)

*0 compliance badge(s) detected*

- **[INFO]** No compliance badges detected — No recognized compliance certification badges or seals were found. This is common — many sites do not display compliance badges.

---

## Availability

### CDN & Delivery (A+ — 100/100)

*Fastly (HIT)*

- **[PASS]** Site is served via Fastly CDN
- **[PASS]** CDN cache status: HIT

### HTTP Caching (A+ — 100/100)

*max-age=600 (10 minutes)*

- **[PASS]** Cache-Control header is set
- **[PASS]** Effective TTL: 10 minutes (max-age=600)
- **[PASS]** ETag present — enables conditional (304) responses
- **[PASS]** Last-Modified header present

### Transport Security (B — 75/100)

*HTTP/3, HSTS, and TLS version analysis*

- **[INFO]** HTTP/3 (QUIC) not advertised — HTTP/3 eliminates head-of-line blocking. If your CDN supports it, consider enabling it.
- **[WARNING]** Missing Strict-Transport-Security header — HSTS tells browsers to only use HTTPS, preventing SSL stripping attacks.
- **[PASS]** TLS 1.3 in use (fastest handshake, 1-RTT)

---

## Accessibility

### Landmark Structure (A — 85/100)

*9 landmarks*

- **[PASS]** <main> landmark present
- **[PASS]** 5 <nav> landmark(s) found
- **[PASS]** All <nav> elements are properly labeled
- **[WARNING]** Skip navigation link is missing (WCAG 2.4.1) — Add a skip link as the first focusable element so keyboard users can bypass repeated navigation.
- **[PASS]** Search landmark present

### Heading Hierarchy (A+ — 95/100)

*1 headings*

- **[PASS]** Single H1 present
- **[WARNING]** 1 empty heading(s) — Empty headings appear in the document outline but provide no information.

### Alt Text Quality (A — 94/100)

*2 of 2 images have issues*

- **[WARNING]** 2 image(s) with generic alt text

### Form Accessibility (A — 85/100)

*1 of 5 controls have issues*

- **[CRITICAL]** 1 control(s) without accessible label — Form controls need a <label>, aria-label, or aria-labelledby for screen readers.
- **[PASS]** 4 control(s) properly labeled

### Link & Button Quality (A — 88/100)

*30 links, 3 buttons — all OK*

- **[WARNING]** 16 link(s) open in new tab without warning — Add '(opens in new tab)' to link text or aria-label.
- **[PASS]** 14 link(s) with descriptive text

---

## UX

### 404 Error Page (B — 70/100)

*HTTP 404, custom page*

- **[PASS]** Correct 404 status code returned
- **[PASS]** Custom styled 404 page
- **[PASS]** Navigation links present on 404 page

### Favicon & Branding (F — 15/100)

*1 icon(s) detected*

- **[WARNING]** No favicon.ico at site root — Some older browsers, bookmark tools, and RSS readers look for /favicon.ico. Add one as a fallback.
- **[PASS]** HTML icon links detected
- **[INFO]** No apple-touch-icon detected — iOS devices use this when users add your site to their home screen. Add <link rel='apple-touch-icon' sizes='180x180' href='/apple-touch-icon.png'>.

### Web Manifest (D — 40/100)

*Not found*

- **[INFO]** No web manifest found — No manifest at standard paths (/manifest.json, /site.webmanifest). A manifest is optional but enables PWA features like home screen installation and standalone display.

### Dark Mode Support (A+ — 100/100)

*Full dark mode support*

- **[PASS]** color-scheme meta tag present — The site declares support for light and dark color schemes via <meta name='color-scheme'>.
- **[PASS]** Dark-specific theme-color detected — A theme-color with media='(prefers-color-scheme: dark)' adapts the browser toolbar for dark mode.
- **[PASS]** prefers-color-scheme CSS detected in inline styles
- **[INFO]** Detection limited to meta tags and inline styles — External CSS files may contain prefers-color-scheme rules not visible to this scan.

### Print Stylesheet (D — 40/100)

*No print styles*

- **[INFO]** No print-specific styles detected — When users print this page, they get the screen layout including navigation and non-essential elements. Add @media print rules to hide navigation and optimize layout for paper.

### Navigation UX (F — 35/100)

*1 navigation pattern(s)*

- **[PASS]** Search functionality detected
- **[PASS]** 5 navigation landmark(s) detected

---

## SEO

### Canonical URL (A+ — 100/100)

*Properly configured*

- **[PASS]** Canonical tag present
- **[PASS]** Canonical is self-referencing
- **[PASS]** Canonical matches final URL after redirects
- **[PASS]** Canonical target returns 200

### Meta Tags (A — 90/100)

*Title: 28 chars*

- **[PASS]** Page title is set
- **[WARNING]** Title is only 28 characters — consider expanding

### Content Depth (F — 25/100)

*193 words, Fairly Easy*

- **[WARNING]** Page has 193 words — thin content — Most well-ranking pages have 300+ words of substantive content.
- **[INFO]** Text-to-HTML ratio is 3% — Very low ratio suggests heavy framework overhead or boilerplate.
- **[INFO]** Reading level: Fairly Easy (grade 4)
- **[WARNING]** Thin content — only 193 words

### Internal Links (A+ — 100/100)

*14 internal, 16 external*

- **[PASS]** 14 internal links (47%)
- **[PASS]** 100% of links use descriptive anchor text
- **[INFO]** 14 internal / 16 external links

### Image SEO (A+ — 100/100)

*2 images, 2 descriptive filenames*

- **[PASS]** All images have descriptive filenames

### Hreflang

*0 hreflang tags*


---

## Sustainability

### CO2 Per Page Load (A+ — 100/100)

*0.09g CO2 per view*

- **[PASS]** 0.09g CO2 per page view — This page transfers 0.4 MB, producing an estimated 0.09g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.00g, network 0.02g, end-user device 0.07g.
- **[INFO]** At 10,000 monthly views: 11.2 kg CO2/year — With 10,000 page views per month, this page would generate approximately 11.2 kg of CO2 annually — equivalent to charging 1401 smartphones.
- **[PASS]** Green hosting reduces data center emissions

### Green Hosting (A+ — 100/100)

*Green (both)*

- **[PASS]** Both hosting and CDN use renewable energy
- **[INFO]** GitHub Pages: Hosted on Azure/GitHub with Microsoft carbon-negative commitment
- **[INFO]** Fastly: 100% renewable energy for edge network
- **[INFO]** Green hosting status based on known provider commitments — Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.

### Repeat Visit Weight (A+ — 100/100)

*99% cached*

- **[PASS]** 99% reduction on repeat visits — Returning visitors download only 5 KB (vs 404 KB first visit). 16 of 17 resources are served from browser cache, saving 0.09g CO2 per repeat visit.
- **[INFO]** Repeat visit: 0.00g CO2 (first visit: 0.09g)

### Carbon Budget (A+ — 100/100)

*10th percentile*

- **[PASS]** 0.09g CO2 — below the sustainability target of 0.50g — Cleaner than an estimated 90% of websites analyzed. This page meets the Web Sustainability Guidelines target.
- **[INFO]** Estimated 10th percentile — Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.

### Transfer Efficiency (C — 60/100)

*70% efficient*

- **[WARNING]** Transfer efficiency: 70% — An estimated 121 KB (30%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 121 KB of unused JavaScript. This wasted data produces 0.03g of unnecessary CO2 per page view.

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*Generated by [BeaverCheck](https://beavercheck.com) — https://beavercheck.com/results/8d24caa5-75a7-46a7-bb46-ef06acff5d70*