Which behavior occurs when a browser encounters a ‘preload’ link tag with an incorrect ‘as’ attribute?

When using ``, the 'as' attribute is mandatory for the browser to set the correct request headers (like Accept) and prioritize the resource correctly. If the 'as' attribute is missing or invalid, the browser will still fetch the resource, but it will trigger a console warning because it cannot apply the correct security policies or priority, potentially leading to a double-download if the resource is later requested via a standard tag.