I am able to change the favicon by setting the argument icon on a template. But this does not seem to work on for Safari and I either get the Panel or Bokeh favicon. Looking at the HTML output, we do see this line:
<link rel="apple-touch-icon" sizes="180x180" href="{{ dist_url }}images/apple-touch-icon.png">
Is there a way to override things in the preamble which do not seem to be templated?