Use any emoji as SVG favicon
Now that all modern browsers support SVG favicons, here's how to turn any emoji into a favicon.svg:
<svg xmlns="http://w3.org/2000/svg" viewBox="0 0 100 100"> <text y=".9em" font-size="90">💩</text> </svg>
Useful for quick apps when you can't be bothered to design a favicon!
I use this a lot for side projects for quickly whipping up a favicon.