March 27, 2018
The new Google Sites provides a simple and elegant way to create websites. To help your site stand out, you can now customize your favicon—the icon which appears in a browser tab or bookmark list—to match your site. This can help your viewers more easily recognize your site, and help you reinforce your branding.
Use Google's Help Center to find out how to add a custom favicon in the new Google Sites
Source: G Suite Blog