<svg xmlns="http://w3.org/2000/svg" viewBox="0 0 100 100">
  <text y=".9em" font-size="90">👾</text>
</svg>

Reference:

More description SVG favicons and favicons maintain general:

• https://css-tricks.com/svg-favicons-and-all-the-fun-things-we-can-do-with-them
• https://dev.to/masakudamatsu/favicon-nightmare-how-to-maintain-sanity-3al7 ← Good one 👌