Volgens
https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel:
Note: The shortcut link type is often seen before icon, but this link type is non-conforming, ignored and web authors must not use it anymore.
<link href="/assets/styles/bootstrap-5.3.0/css/bootstrap.min.css" rel="stylesheet">
<link href="/assets/styles/org-htmlize.css" rel="stylesheet">
<link rel="webmention" href="https://www.vanrenterghem.biz/webmention">
- <link rel="SHORTCUT ICON" href="/assets/favicon.ico" />
+ <link rel="icon" href="/assets/favicon.ico" />
<meta charset="utf-8" />
<title>{{title}}</title>