What this tool checks
Three small but frequently-forgotten files: /favicon.ico (the icon shown in browser tabs and bookmarks), /apple-touch-icon.png (the icon used when a page is bookmarked or added to the home screen on iOS), and a web app manifest (/site.webmanifest or /manifest.json, which describes the site for "Add to Home Screen" on Android and other manifest-aware contexts).
Why these small details matter
None of these files affect whether a site "works," which is exactly why they're so often missing — nothing breaks visibly when they're absent, so they're easy to skip during a rushed launch. But their absence is highly visible to users: a generic gray icon in a browser tab, or a plain unbranded shortcut after "Add to Home Screen," both read as unfinished or untrustworthy, disproportionately to how small the fix actually is.
What counts as "found" here
For the favicon and Apple touch icon, this tool checks that the file responds with an HTTP 200 status at its conventional root path. For the manifest, it additionally verifies the response body is valid, parseable JSON — a manifest that returns a 200 status but broken JSON will fail silently in real browsers, so this tool surfaces that distinction rather than treating any 200 response as success.