Rudder

Yt they are in the JSON returned by the API rudder/secure/api/groups/tree , under the targets (and in 2 categories)

{
   "action":"getGroupTree",
   "result":"success",
   "data":{
      "groupCategories":{
         "id":"GroupRoot",
         "name":"Root of the group and group categories",
         "description":"This is the root category for the groups (both dynamic and static) and group categories",
         "parent":"GroupRoot",
         "categories":[
            {
               "id":"SystemGroups",
               "name":"System groups",
               "description":"That category holds all the system and special target",
               "parent":"GroupRoot",
               "categories":[

               ],
               "groups":[
                  {
                     "id":"all-nodes-with-cfengine-agent",
                     "displayName":"All classic Nodes",
                     "description":"All classic Nodes known by Rudder (Using a CFEngine based agent)",
                     "category":"SystemGroups",
                     "query":{
                        "select":"nodeAndPolicyServer",
                        "composition":"And",
                        "where":[
                           {
                              "objectType":"node",
                              "attribute":"agentName",
                              "comparator":"eq",
                              "value":"cfengine" 
                           }
                        ]
                     },
                     "nodeIds":[
                        "66185216-2ebf-4b97-b0cd-99d628bb3f96",
                        "root" 
                     ],
                     "dynamic":true,
                     "enabled":true,
                     "groupClass":[
                        "group_all_classic_nodes",
                        "group_all_nodes_with_cfengine_agent" 
                     ],
                     "properties":[

                     ],
                     "system":true,
                     "target":"group:all-nodes-with-cfengine-agent" 
                  },
                  {
                     "id":"hasPolicyServer-root",
                     "displayName":"All classic Nodes managed by root policy server",
                     "description":"All classic Nodes known by Rudder directly connected to the root server. This group exists only as internal purpose and should not be used to configure nodes.",
                     "category":"SystemGroups",
                     "query":{
                        "select":"nodeAndPolicyServer",
                        "composition":"And",
                        "where":[
                           {
                              "objectType":"node",
                              "attribute":"policyServerId",
                              "comparator":"eq",
                              "value":"root" 
                           },
                           {
                              "objectType":"node",
                              "attribute":"agentName",
                              "comparator":"eq",
                              "value":"cfengine" 
                           }
                        ]
                     },
                     "nodeIds":[
                        "66185216-2ebf-4b97-b0cd-99d628bb3f96",
                        "root" 
                     ],
                     "dynamic":true,
                     "enabled":true,
                     "groupClass":[
                        "group_all_classic_nodes_managed_by_root_policy_server",
                        "group_haspolicyserver_root" 
                     ],
                     "properties":[

                     ],
                     "system":true,
                     "target":"group:hasPolicyServer-root" 
                  }
               ],
               "targets":[
                  {
                     "id":"policyServer:root",
                     "displayName":"Root policy server",
                     "description":"Only the root policy server",
                     "enabled":true,
                     "target":"policyServer:root" 
                  },
                  {
                     "id":"special:all_exceptPolicyServers",
                     "displayName":"All managed nodes",
                     "description":"All nodes known by Rudder (excluding Rudder policy servers)",
                     "enabled":true,
                     "target":"special:all_exceptPolicyServers" 
                  },
                  {
                     "id":"special:all",
                     "displayName":"All nodes",
                     "description":"All nodes known by Rudder (including Rudder policy servers)",
                     "enabled":true,
                     "target":"special:all" 
                  }
               ]
            }
         ],
         "groups":[

         ],
         "targets":[
            {
               "id":"policyServer:root",
               "displayName":"Root policy server",
               "description":"Only the root policy server",
               "enabled":true,
               "target":"policyServer:root" 
            },
            {
               "id":"special:all_exceptPolicyServers",
               "displayName":"All managed nodes",
               "description":"All nodes known by Rudder (excluding Rudder policy servers)",
               "enabled":true,
               "target":"special:all_exceptPolicyServers" 
            },
            {
               "id":"special:all",
               "displayName":"All nodes",
               "description":"All nodes known by Rudder (including Rudder policy servers)",
               "enabled":true,
               "target":"special:all" 
            }
         ]
      }
   }
}

Work in progess here: https://github.com/ncharles/rudder/commit/e16ae3b02b39920e6e5569dd12a518280b60fe1b