diff --git a/server/topic.go b/server/topic.go
index 946f364ca3db565824690cf2263952ef53c16716..03cc78c4396f0edfcfb66086be650029a8e3e4b2 100644
--- a/server/topic.go
+++ b/server/topic.go
@@ -965,7 +965,7 @@ func (t *Topic) saveAndBroadcastMessage(msg *ClientComMessage, asUid types.Uid,
 	}
 
 	if msg.sess != nil && msg.sess.uid != asUid {
-		// Add 'sender' header indicating that message was sent on behalf of another user.
+		// The "sender" header contains ID of the user who sent the message on behalf of asUid.
 		if head == nil {
 			head = map[string]interface{}{}
 		}