favicon

Source: https://evilmartians.com/chronicles/how-to-favicon-in-2021-six-files-that-fit-most-needs

See site for full explanation but TLDR from site is:

Instead of serving dozens of icons, all you need is just five icons and one JSON file.

For the browser using HTML:

<link rel="icon" href="/favicon.ico" sizes="32x32">
<link rel="icon" href="/icon.svg" type="image/svg+xml">
<link rel="apple-touch-icon" href="/apple-touch-icon.png"><!-- 180×180 -->

If you’re making a PWA (Progressive Web App), also add this to the HTML:

<link rel="manifest" href="/manifest.webmanifest">

And a file with the web app manifest:

// manifest.webmanifest
{
"icons": [
{ "src": "/icon-192.png", "type": "image/png", "sizes": "192x192" },
{ "src": "/icon-mask.png", "type": "image/png", "sizes": "512x512", "purpose": "maskable" },
{ "src": "/icon-512.png", "type": "image/png", "sizes": "512x512" }
]
}

Maskable icons should have bigger paddings. The safe zone is a 409×409 circle. Use maskable.app to check your icon.