Frontend Service: localhost:8080/api/
The frontend service is the only available service. The configuration has zuul.ignored-services: '*' and an explicit mapping for the frontend service. If you omit this setting all eureka services are published by zuul.
You can find the configuration here: application.yml.
The default Zuul implementation doesn't return the tracing information to a client. This might be a problem if you need to debug an issue reported by an external user or system. I would favor the forwarding of the span-Id to aid debugging so you can see the id in the error reports. If you have these Ids you can simply find all related tracing information.
The SleuthResponseFilter adds the tmx-correlation-id HTTP Header.
➜ cloud-demo git:(master) ✗ http http://localhost:8080/api/
HTTP/1.1 200
Content-Type: text/plain;charset=UTF-8
Date: Thu, 19 Oct 2017 04:20:13 GMT
Transfer-Encoding: chunked
X-Application-Context: edgeservice:default:8080
tmx-correlation-id: 3b2466c39096a21f
The result will be a number.