diff --git a/src/net/http/http.go b/src/net/http/http.go
index 4da77889b1a..32ff7e2008a 100644
--- a/src/net/http/http.go
+++ b/src/net/http/http.go
@@ -17,6 +17,7 @@ import (
 )
 
 // Protocols is a set of HTTP protocols.
+// The zero value is an empty set of protocols.
 //
 // The supported protocols are:
 //