_includes/head/custom.html

<!-- insert favicons. use https://realfavicongenerator.net/ -->
<link rel="icon" 
      type="image/png" 
      href="{{site.baseurl}}/media/pages/new_app_service_logo_16.png">
<link rel="shortcut icon" 
      type="image/png" 
      href="{{site.baseurl}}/media/pages/new_app_service_logo_16.png">