msc {
  hscale = "1.5";

  a  [ label = "Alice" ],
  bb [ label = "Bob Server" ];

  ... [ label = "Webfinger RFC 7033" ];

  --- [ label = "optional for webfinger url tpl" ];
  ... [ label = "RFC 6415" ];
  a  -> bb [ label = "GET /.well-known/host-meta" ] ;
  bb ->  a [ label = "application/xrd+xml" ] ;

  ... ;

  --- [ label = "mandatory for actor profile url" ];
  a  -> bb [ label = "GET /.well-known/webfinger?query=acct:bob@example.com" ] ;
  bb ->  a [ label = "application/jrd+json" ] ;
}
