HTTP protocol RFC pretty explicitly says that the Request-URI transmitted is a "path" and refers to URI RFC to define "path". There is really no ambiguity here,

HTTP protocol RFC pretty explicitly says that the Request-URI transmitted is a "path" and refers to URI RFC to define "path". There is really no ambiguity here, HTTP as a protocol expects resources to be organized as an hierarchy and accessed via a path, which is delimited by "/" characters. As such the protocol definitely reserves and assigns special meaning to "/" in paths. Of course servers are perfectly free to do whatever they want, there is no HTTP police to stop them.