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"/>