The `r.on "register"` block will run for requests starting with /register. The `r.on "boop"` block inside that will run for requests starting with /register/boop. If the request is a GET request for /register/boop/wut, it will return "wut". If the request is any other GET request starting with /register/boop (including /register/boop, /register/boop/, and /register/boop/anything/else), it runs "boop". You may want to change the `r.get` call to `r.get true` so that it only matches GET requests for /register/boop, and not other GET requests starting with /register/boop. The true argument to r.get triggers a terminal match (r.get without arguments does not force a terminal match).