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.
Despite this, many websites still use this link type and browsers still support it.
This should either be supported ("don't break the web"-style) or documented as explicity not supported.
According to MDN
Despite this, many websites still use this link type and browsers still support it. This should either be supported ("don't break the web"-style) or documented as explicity not supported.
Examples
https://hardwaretester.com/gamepad
<link rel="shortcut icon" href="/favicon.png">https://www.eorc.jaxa.jp/ALOS/en/dataset/aw3d30/aw3d30_e.htm
<link rel="shortcut icon" href="../../../images/common/favicon_a.ico">