Show HN: Web Environment Integrity warning banner for websites

If a visitor is using a WEI-enabled browser (e.g. Chrome, Edge, Chromium) they will get a full-page warning that their browser is harmful, with a link to the FSF's explanation of why WEI is bad and download links to various browsers that oppose WEI (currently: Firefox, Safari, Brave, Pale Moon, GNOME Web).

The user has to close the warning banner to view the website content.