In HTTP, information about the media type of a representation of a resource is given out of band from the resource's URL, obviating the need for file extensions as type indicators. Information architects and/or interaction designers are free to do away with file extensions entirely and reclaim the period character . for any one of its original purposes, like a decimal point. File extensions in HTTP URLs are nothing more than a superfluous vestige of a long-expired implementation constraint, and can be safely discarded.

If there is any further trepidation around eliminating file extensions, especially with respect to saving Web pages, rest assured that modern browsers append the necessary extensions in the save dialogue box. For resources like Adobe PDFs that are intended to only be downloaded and saved as files, there is a specific technique to supply a file name independently of the URL.