'@' symbols returned in flow programmer rest api

In the REST API documentation I found here:
https://jenkins.opendaylight.org/controller/job/controller-merge/ws/opendaylight/northbound/flowprogrammer/target/site/wsdocs/el_ns0_flowConfigs.html

It says the formatting of the json output should look like:
"node" :

{ "id" : "...", "type" : "..." }

, ...and so on

When I look at a flow via the REST api that I have configured via
> curl -u admin:admin http://10.10.10.80:8080/controller/nb/v2/flow/default/OF/00:00:00:50:56:9b:32:28/public-firewall-ipv4-in_to_out

I get this output:
{"installInHw":"true","name":"public-firewall-ipv4-in_to_out","node":

{"@id":"00:00:00:50:56:9b:32:28","@type":"OF"}

,"ingressPort":"2","priority":"500","etherType":"0x800","actions":"OUTPUT=1"}

Note the '@' characters in the flow node 'id' and 'type' fields
which conflict with the names in the documentation.

I also note that when trying to add (POST) a new flow via the rest
api the controller also seems to want those '@' symbols in the 'id'
and 'type' fields.