Containing any leading slashes means that the URI contains a path, which means that it represents a location, which automatically makes it an URL and not an URN. Can you direct me to an IETF or a W3C document that says that? The only official text that I know of that distinguishes URIs and URLs is the section from URI RFC (already linked in this thread several times) and it explicitly says that
В письме от четверг, 9 июня 2022 г. 02:18:07 MSK пользователь Gavin Lambert via Boost написал: the difference between a URI and a URL is not in syntax, but in intent. Furthermore, the RFC calls "path" the part between (optional) "//" authority and (optional) "?" query. It explicitly says that path is required, but it can be empty. As such me@server.tld in mailto:me@server.tld is path. Is it a URL by your definition? Conversely, the path for http://example.com is empty. Is it still a URL?
Any URI that uses the http protocol is (by definition) an URL, because it is representing a location. Again, can you direct me to a document that spells out this feature of the http scheme?