We are wondering how to add a favicon icon to SSPR 4.x

We are moving from SSPR 3.x where we manually added the favicon.ico file to the correct directory as with the .css files for branding. Now, with uploading a .zip file for branding, there's zero mention of how to manage the favicon. And SSPR 4.x seems to use a favicon.png file instead of favicon.ico

Any documentation regarding favicon in SSPR?