diff --git a/spec.bs b/spec.bs
index 07b0a6d..64d32b1 100644
--- a/spec.bs
+++ b/spec.bs
@@ -1774,6 +1774,7 @@ To <dfn>convert a modifier to a string</dfn> given a [=part/modifier=] |modifier
   1. Let |dummyURL| be the result of [=creating a dummy URL=].
   1. If |protocolValue| was given, then set |dummyURL|'s [=url/scheme=] to |protocolValue|.
      <p class="note">Note, we set the [=URL record=]'s [=url/scheme=] in order for the [=basic URL parser=] to recognize and normalize default port values.</p>
+  1. Otherwise, set |dummyURL|'s [=url/scheme=] to the empty string.
   1. Let |parseResult| be the result of running [=basic URL parser=] given |portValue| with |dummyURL| as <i>[=basic URL parser/url=]</i> and [=port state=] as <i>[=basic URL parser/state override=]</i>.
   1. If |parseResult| is failure, then throw a {{TypeError}}.
   1. Return |dummyURL|'s [=url/port=], [=serialize an integer|serialized=], or empty string if it is null.