Add links to MP and resolve minor fixes

appengine/swarming/handlers_endpoints.py

Index: appengine/swarming/handlers_endpoints.py
diff --git a/appengine/swarming/handlers_endpoints.py b/appengine/swarming/handlers_endpoints.py
index 03302a2f6f571d89a570ef1763687c58b093fa94..7dfa7388e12431b8eb91e7dfb965e5028fae721a 100644
--- a/appengine/swarming/handlers_endpoints.py
+++ b/appengine/swarming/handlers_endpoints.py
@@ -135,9 +135,17 @@ class SwarmingServerService(remote.Service):
   def details(self, _request):
     """Returns information about the server."""
     host = 'https://' + os.environ['HTTP_HOST']
+
+    mpp = ''
+    if config.settings().mp and config.settings().mp.server:
+      mpp = config.settings().mp.server
+
     return swarming_rpcs.ServerDetails(
         bot_version = bot_code.get_bot_version(host),
-        server_version = utils.get_app_version())
+        server_version = utils.get_app_version(),
+        machine_provider_prefix = mpp,
+        milo_prefix = config.settings().milo_server_prefix,
+        sk_revision_prefix = config.settings().sk_revision_prefix)
 
   @gae_ts_mon.instrument_endpoint()
   @auth.endpoints_method(