Check your favicon tags
Paste the head of your page and ConvertICO reads out every icon link it finds: the file, the size, the purpose, and which recommended ones are absent. It parses the markup here, so nothing is fetched or sent anywhere.
Parsed here in your browser. Nothing is fetched and nothing is sent anywhere.
How it works
Copy the head of your page, paste it above, and ConvertICO reads out every favicon and app-icon link it can find: the rel value, any declared size, and the file each one points at. It also flags the recommended pieces that are missing, like an Apple touch icon or a web app manifest. Because it only reads the markup you paste, it never touches the network, which means you can check a staging site or a page behind a login without anything leaving your browser.
Runs entirely in your browser. Your file is never uploaded.