It might be reasonable to prefix match on both, I think push-state patterns are still relatively rare due to browser support. It might still be common to encode some UI state in the fragment that's not intended to be sent to the server or persisted. In those cases we might still see key/value or path encodings. It's more general if we can support both. I'm hoping there's a nice way to repurpose one of the URI Template operators to indicate the intention in the template.