The prerender-status-code meta element (sometimes referred to as meta tag) is not an official meta tag and there is no documentation on it at the Worldwide Web Consortium (W3C.org), where the official HTML standards are created. and their behavior may not be consistent across different browsersThe prerender-status-code meta element is an example of a non-standard meta element that also happens to not be supported by Google. Another non-standard meta element that is not supported by Google is the meta keywords element. The X-UA-Compatible meta element is an example of a browser-specific non-standard meta element that is an outdated meta element that was specific to the old Internet Explorer web browser. Those non-official meta elements are called non-standard meta elements.