Why it matters
Browsers request /favicon.ico anyway (a 404 on every page), tabs and bookmarks show a blank icon and search results show a generic globe. An SVG-only icon isn't supported by Safari and some crawlers.
How to fix it
Add app/icon.png (or favicon.ico) plus app/apple-icon.png; keep icon.svg as an extra, not the only icon.
Example
app/favicon.ico
app/icon.svg
app/apple-icon.png (180×180)References
More lint rules
void lint reports 67 rules in this category. Static source checks with no browser: Tailwind v4 silent failures, Next.js 16 API traps, React render-body bugs, accessibility markup, SEO files and motion hygiene.
not-found-in-suspense`notFound()`/`redirect()` inside a component rendered under `<Suspense>`missing-sitemapNo sitemapmissing-robotsNo robots.txtmissing-og-imageNo Open Graph image anywheremissing-llms-txtNo `/llms.txt`dynamic-metadata-streamingRequest-time `generateMetadata` without `htmlLimitedBots`missing-langRoot `<html>` without `lang`jsonld-missingNo JSON-LD structured data