When opening a locally stored HTML file, WebKit-based browsers will fail to load the favicon referenced from the HTML file and hence will not display any icon for the tab. Example <link> tag that doesn't work: <link rel="shortcut icon" href="_static/favicon.ico"/> I've tried variations on this (e.g. removing "shortcut"), but nothing makes the icon load. Tested with Safari 16 on macOS and Epiphany 42.5 on Linux. All other browsers on all other platforms support this, so it's just WebKit that fails to handle this.
<rdar://problem/112260690>