The "/favicon.ico" page:
Return the default favicon.ico image. The returned image is for the Fossil lizard icon.
The intended use case here is to supply a favicon for the "fossil ui" command. For a permanent website, the recommended process is for the admin to set up a project-specific favicon and reference that icon in the HTML header using a line like:
<link rel="icon" href="URL-FOR-YOUR-ICON" type="MIMETYPE"/>