Use when auditing page weight for crawl efficiency, investigating why certain page content is not appearing in Google's index, or reviewing server-rendered pages that embed large JSON payloads in HTML.
Use when applies to XHTML documents and polyglot HTML documents that must parse correctly as both HTML5 and XML. For modern HTML5-only documents, only lang is needed and xml:lang is not required. Check when auditing documents served as application/xhtml+xml or documents that include both attributes.
Use when reviewing templates, rendered HTML, or shared components related to Use semantic HTML elements. Validate the final browser-facing markup, not just the source framework abstraction.
Use when auditing slow page loads, heavy assets, or rendering delays related to Minimize HTTP requests. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
Use when auditing slow page loads, heavy assets, or rendering delays related to Enable HTTP/2 or HTTP/3. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
Use when auditing a site's internal and external links for protocol consistency, migrating a site from HTTP to HTTPS, or reviewing hardcoded URLs in a codebase that may use http:// instead of https://.
Use when auditing URL structures for word separator format, generating slugs from titles, or planning a URL migration from underscores or spaces to hyphens with appropriate redirects.
Use when reviewing rendered HTML, interactive components, or design-system patterns related to Ensure identical links have consistent destinations. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.
Use when reviewing image assets, markup, and CDN or build transforms related to Serve images from a CDN. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
Use when reviewing image assets, markup, and CDN or build transforms related to Compress images without quality loss. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
Use when auditing the image pipeline, static assets in public/, CMS-managed media, or image CDN transforms. Separate file-size problems from dimension mismatches so you can tell whether the issue is compression, format choice, or responsive delivery.
Use when reviewing image assets, markup, and CDN or build transforms related to Optimize all images for web. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
Use when reviewing rendered HTML, interactive components, or design-system patterns related to Avoid redundant image alternative text. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.
Use when reviewing scripts, client components, bundles, or runtime behavior related to Prefer immutable data patterns. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug.
Use when reviewing slow initial loads caused by optional features. Prioritize code that is expensive to download or execute and not required for the first viewport, first input, or core task completion.
Use when reviewing long pages, dashboards, or content feeds with expensive offscreen modules. Balance early enough loading for smooth scrolling against keeping the initial route light.
Use when reviewing or improving a Front-End Checklist rule MDX file to raise its quality score, fix stub prompts, add missing fields, or enrich content with real code examples.
Use when reviewing rendered HTML, interactive components, or design-system patterns related to Use inclusive language. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.
Use when auditing a site for indexability issues, investigating why pages appear in Google's index that should be excluded (or vice versa), or reviewing robots.txt and meta robots configurations for consistency.
Use when auditing a site for accidental noindex directives, investigating why important pages are not appearing in Google Search, or reviewing CMS settings that control indexing at the page or category level.
Use when reviewing rendered HTML, interactive components, or design-system patterns related to Provide alt text for image buttons. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.
Use when reviewing templates, rendered HTML, or shared components related to Use semantic input type attributes. Validate the final browser-facing markup, not just the source framework abstraction.
At most 3 mods per repository are shown here, and a mod shipped inside a plugin is left to that plugin's page β the rest are on their repository pages: