I'm surprised that you find that inconsistent and confusing, since there are common schemes that don't use the hierarchical `//host/path` syntax, e.g. `mailto:`, `magnet:?xt=urn:sha1:`, `tel:+1-816-555-1212`, `skype:echo?call`, `spotify:track:`.

A URL `flags://gb` would mimic hierarchical URLs where `//gb` addresses a hostname called `gb`.