# BeaverCheck Audit Report — https://scikit-learn.org

**Date:** April 22, 2026  
**URL:** https://scikit-learn.org  
**Overall Grade:** C (74/100)  
**Report:** https://beavercheck.com/results/2baf4c38-9a61-4c7e-ae58-b019dc56c7fe

## 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]** 9 image(s) missing alt attribute — Accessibility > Alt Text Quality
5. **[CRITICAL]** 9 image-in-link without alt text — Accessibility > Alt Text Quality

---

## Lighthouse Scores

| Category | Score |
|----------|-------|
| Performance | 52 |
| Accessibility | 95 |
| Best Practices | 73 |
| SEO | 92 |

---

## 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 35 days)
- **[PASS]** Certificate chain has 2 certificates
- **[PASS]** Certificate uses modern signature algorithm
- **[PASS]** Certificate covers 2 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 2 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 views.scientific-python.org 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 (A+ — 100/100)

*DMARC: reject*

- **[PASS]** DMARC policy is reject — strongest protection

### 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 (C — 68/100)

*1.6 MB transferred, 75 requests*

- **[INFO]** Page weighs 3.0 MB (1.6 MB transferred)
- **[WARNING]** JavaScript is 590 KB — consider code splitting or lazy loading — Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
- **[INFO]** Fonts are 268 KB — consider subsetting or using system fonts — Subset fonts to include only used characters, or switch to system font stacks.
- **[INFO]** 75 HTTP requests
- **[INFO]** Estimated 0.33 g CO2 per page load

### Third-Party Impact (A+ — 100/100)

*0% third-party, 0 ms blocking*

- **[INFO]** Third-party code accounts for 0% of page weight (2.7 KiB of 1.6 MiB)
- **[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 (C — 60/100)

*22 images, 0 KB saveable*

- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/nvidia-sma... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/czi-small.... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/wellcome-t... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/scikit-lea... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/chanel-sma... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/bnp-pariba... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/quansight-... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/probabl.pn... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/sphx_glr_p... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_images/inria.png is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/inria-smal... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.
- **[WARNING]** https://scikit-learn.org/stable/_static/microsoft-... is missing width/height — may cause layout shift — Set explicit width and height to prevent CLS.

### JS Execution Cost (C — 60/100)

*1382ms total JS execution*

- **[WARNING]** https://scikit-learn.org/stable/_static/scripts/fo...: 490ms CPU time
- **[WARNING]** Unattributable: 404ms CPU time
- **[WARNING]** https://scikit-learn.org/stable/: 374ms CPU time
- **[INFO]** https://scikit-learn.org/stable/_static/styles/pyd...: 60ms CPU time
- **[INFO]** https://scikit-learn.org/stable/_static/scripts/bo...: 54ms CPU time
- **[INFO]** Third-party scripts: 404ms (29% of total)

### Font Loading (A+ — 100/100)

*2 fonts (268 KB)*

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

### JS Bundles (A+ — 100/100)

*20 scripts, 0 KB unused*


### 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)

*2 hints, 0 missing preconnects*

- **[PASS]** Page uses 2 resource hint(s)

### Page Weight Inventory (C — 60/100)

*75 resources · 1.6 MB · 0 KB savings available*

- **[WARNING]** Page weight 599 KB over 1MB target
- **[INFO]** 5 third-party resources (0% 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 (F — 40/100)

*120 links checked, 25 healthy, 95 broken*

- **[CRITICAL]** 25 of 120 links are healthy
- **[WARNING]** Broken link: https://scikit-learn.org/_static/styles/theme.css?digest=... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/styles/pydata-sphinx-the... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/pygments.css?v=8f2a1f02 — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/copybutton.css?v=76b2166b — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/plot_directive.css — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/jupyterlite_sphinx.css?v... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sg_gallery.css?v=d2d258e8 — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sg_gallery-binder.css?v=... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sg_gallery-dataframe.css... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sg_gallery-rendered-html... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sphinx-design.min.css?v=... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/styles/index.css?v=e49e61c4 — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/styles/colors.css?v=cc94... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/styles/custom.css?v=eec3... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/fontawesome.js?d... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/bootstrap.js?dig... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/pydata-sphinx-th... — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/documentation_options.js... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/doctools.js?v=9bcbadda — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/sphinx_highlight.js?v=dc... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/clipboard.min.js?v=a7894cd8 — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/copybutton.js?v=97f0b27d — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/jupyterlite_sphinx.js?v=... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/design-tabs.js?v=f930bc37 — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/dropdown.js?v=d6... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/version-switcher... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/sg_plotly_resize... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scripts/theme-observer.j... — Found in <script src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/favicon.ico — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/about.html — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/search.html — Found in <link href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/scikit-learn-logo-withou... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/install.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/user_guide.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/api/index.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/index.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/getting_started.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/whats_new.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/glossary.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/faq.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/support.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/related_projects.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/roadmap.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/governance.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/release_highlights... — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/supervised_learning.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/ensemble.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/neighbors.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/linear_model.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/classification/plo... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_classifier... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/classification/ind... — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/ensemble/plot_hgbt... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_hgbt_regre... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/clustering.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/cluster/plot_kmean... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_kmeans_dig... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/cluster/index.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/decomposition.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/feature_selection.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/decomposition/plot... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_pca_iris_t... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/decomposition/inde... — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/model_selection.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/grid_search.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/cross_validation.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/model_evaluation.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/model_selection/pl... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_multi_metr... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/model_selection/in... — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/preprocessing.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/modules/feature_extraction.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/preprocessing/plot... — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/sphx_glr_plot_discretiza... — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/auto_examples/preprocessing/inde... — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/whats_new/v1.8.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/whats_new/v1.7.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/whats_new/v1.6.html — Found in <a href>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://www.instagram.com/scikitlearnofficial/ — Found in <a href>. Returns HTTP 429.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/inria.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/spotify.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/change-logo.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/telecomparistech.jpg — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/aweber.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_images/yhat.png — Found in <img src>. Returns HTTP 404.
- **[CRITICAL]** Broken link: https://scikit-learn.org/testimonials/testimonials.html — Found in <a href>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/probabl.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/inria-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/chanel-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/bnp-paribas.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/microsoft-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/nvidia-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/quansight-labs-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/czi-small.png — Found in <img src>. Returns HTTP 404.
- **[WARNING]** Broken link: https://scikit-learn.org/_static/wellcome-trust-small.png — Found in <img src>. Returns HTTP 404.

### 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+ — 100/100)

*4 A records, 103 ms lookup*

- **[PASS]** Resolves to 4 IPv4 address(es)
- **[INFO]** No IPv6 (AAAA) records
- **[PASS]** 3 nameserver(s) configured
- **[PASS]** 2 mail exchanger(s) configured
- **[INFO]** CAA records not checked — CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
- **[PASS]** SPF record present in TXT
- **[PASS]** DNS resolution time: 103 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 (B — 75/100)

*no robots.txt, no sitemap*

- **[INFO]** No robots.txt found — robots.txt is optional but recommended. It tells search engine crawlers which pages to index.
- **[INFO]** No sitemap.xml found — A sitemap helps search engines discover and index your pages more efficiently.

### URL Variants (B — 75/100)

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

- **[PASS]** www/non-www redirect configured correctly (preferred: non-www)
- **[CRITICAL]** HTTP version does not redirect to HTTPS

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

*scikit-learn.org — via Gandi SAS, 14 years, 8 months old, hosted on Fastly*

- **[PASS]** Domain registered until Oct 19, 2029 (3 years, 6 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 (C — 55/100)

*1 trackers detected*

- **[INFO]** 1 third-party trackers detected — Found 1 analytics, 0 advertising, 0 marketing, 0 tag manager trackers.
- **[WARNING]** Trackers detected but no cookie policy found — This page loads 1 trackers but no cookie policy was detected. GDPR requires disclosure when using tracking cookies.
- **[WARNING]** Trackers detected but no privacy policy found — Most data protection regulations require a privacy policy when collecting user data via trackers.

### Cookie & Tracker Inventory (A+ — 100/100)

*0 cookies · 1 trackers · 0 pre-consent*

- **[INFO]** 1 third-party tracker(s) detected on page

---

## 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 (C — 55/100)

*No copyright notice detected*

- **[INFO]** No copyright notice detected — No copyright notice detected in the page content. While not legally required in most jurisdictions (copyright exists automatically), a notice is standard practice and signals site ownership.

### 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 (B — 75/100)

*6 landmarks*

- **[PASS]** <main> landmark present
- **[WARNING]** Multiple <main> landmarks (2 found) — A page should have only one <main> landmark.
- **[PASS]** 2 <nav> landmark(s) found
- **[WARNING]** 2 of 2 <nav> elements are unlabeled — Multiple navigations need aria-label to distinguish them for screen readers.
- **[INFO]** No contentinfo (footer) landmark
- **[PASS]** Skip navigation link present

### Heading Hierarchy (A — 85/100)

*11 headings, 1 skip(s)*

- **[PASS]** Single H1 present
- **[WARNING]** Heading level skipped: H1 → H4 (missing H2) — Skipping heading levels breaks the document outline. Screen readers may interpret missing levels as structural errors.

### Alt Text Quality (F — 30/100)

*9 of 23 images have issues*

- **[CRITICAL]** 9 image(s) missing alt attribute — Images without alt text are invisible to screen readers.
- **[CRITICAL]** 9 image-in-link without alt text — An image inside a link with no alt creates an empty link.
- **[PASS]** 14 image(s) with good alt text

### Form Accessibility (A+ — 100/100)

*All 1 controls labeled*

- **[PASS]** 1 control(s) properly labeled

### Link & Button Quality (A — 91/100)

*112 links, 9 buttons — all OK*

- **[WARNING]** 3 link(s) open in new tab without warning — Add '(opens in new tab)' to link text or aria-label.
- **[PASS]** 109 link(s) with descriptive text

---

## UX

### 404 Error Page (B — 80/100)

*HTTP 404, custom page*

- **[PASS]** Correct 404 status code returned
- **[PASS]** Custom styled 404 page
- **[PASS]** Navigation links present on 404 page
- **[PASS]** Homepage link 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 (D — 40/100)

*No dark mode signals*

- **[INFO]** No dark mode signals detected — Consider adding CSS with @media (prefers-color-scheme: dark) and <meta name='color-scheme' content='light dark'>.
- **[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]** Skip navigation link detected
- **[PASS]** 2 navigation landmark(s) detected
- **[PASS]** Hamburger menu detected (responsive design)

---

## SEO

### Canonical URL (A — 90/100)

*Minor issues*

- **[PASS]** Canonical tag present
- **[WARNING]** Canonical does not match final URL (https://scikit-learn.org)

### Meta Tags (A — 90/100)

*Title: 77 chars*

- **[PASS]** Page title is set
- **[WARNING]** Title is 77 characters — will be truncated in search results
- **[PASS]** Title and H1 are well-aligned

### Content Depth (B — 80/100)

*502 words, Very Difficult*

- **[PASS]** Page has 502 words of content
- **[INFO]** Reading level: Very Difficult (grade 11)

### Internal Links (A+ — 100/100)

*91 internal, 21 external*

- **[PASS]** 91 internal links (81%)
- **[PASS]** 100% of links use descriptive anchor text
- **[INFO]** 91 internal / 21 external links

### Image SEO (A+ — 95/100)

*23 images, 23 descriptive filenames*

- **[PASS]** All images have descriptive filenames
- **[INFO]** 9 image(s) missing alt text — see Accessibility tab

### Hreflang

*0 hreflang tags*


---

## Sustainability

### CO2 Per Page Load (A — 85/100)

*0.38g CO2 per view*

- **[PASS]** 0.38g CO2 per page view — This page transfers 1.6 MB, producing an estimated 0.38g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.01g, network 0.08g, end-user device 0.29g.
- **[INFO]** At 10,000 monthly views: 45.0 kg CO2/year — With 10,000 page views per month, this page would generate approximately 45.0 kg of CO2 annually — equivalent to charging 5628 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 8 KB (vs 1623 KB first visit). 73 of 75 resources are served from browser cache, saving 0.37g CO2 per repeat visit.
- **[INFO]** Repeat visit: 0.00g CO2 (first visit: 0.38g)

### Carbon Budget (A — 85/100)

*27th percentile*

- **[PASS]** 0.38g CO2 — below the sustainability target of 0.50g — Cleaner than an estimated 73% of websites analyzed. This page meets the Web Sustainability Guidelines target.
- **[INFO]** Estimated 27th percentile — Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.

### Transfer Efficiency (A+ — 100/100)

*100% efficient*

- **[PASS]** Transfer efficiency: 100% — Only 0 KB of potential savings identified. Your page is well-optimized for size.

---

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*Generated by [BeaverCheck](https://beavercheck.com) — https://beavercheck.com/results/2baf4c38-9a61-4c7e-ae58-b019dc56c7fe*