Prop224 says: ``` The hidden service SHOULD NOT reject any LSTYPE fields which it doesn't recognize; instead, it should use them verbatim in its EXTEND request to the rendezvous point. ``` https://gitweb.torproject.org/torspec.git/tree/proposals/224-rend-spec-ng.txt#n1689 We should either remove this from the spec, or we should: * add a similar sentence for client descriptor lspecs * put unrecognised lspecs in descriptors in client intro EXTEND requests * put unrecognised lspecs in INTRODUCE cells in service rend EXTEND requests