docs: updated viewport description

Google APIs · copybara-github · commit 808bc4453437 · 2023-03-13T09:58:22.000-07:00
PiperOrigin-RevId: 516241048
diff --git a/google/maps/fleetengine/delivery/v1/delivery_api.proto b/google/maps/fleetengine/delivery/v1/delivery_api.proto
@@ -309,10 +309,8 @@ message ListDeliveryVehiclesRequest {
   // is 1 restriction.
   string filter = 6 [(google.api.field_behavior) = OPTIONAL];
 
-  // Optional. A filter that limits the search area to a rectangle defined by
-  // the northeast and southwest corner points.
-  //
-  // When defined, only vehicles located within the search area are returned.
+  // Optional. A filter that limits the vehicles returned to those whose last
+  // known location was in the rectangular area defined by the viewport.
   google.geo.type.Viewport viewport = 7
       [(google.api.field_behavior) = OPTIONAL];
 }
