non-normative host hook alternative

spec.emu

@@ -1168,6 +1168,15 @@ contributors: Luca Casonato, Guy Bedford, Nicolò Ribaudo
                 <p><ins>For Module Records that do not have a source representation, GetModuleSource() must always return a throw completion whose [[Value]] is a *ReferenceError*.</ins></p>
               </td>
             </tr>
+            <tr>
+              <td>
+                <ins>GetModuleSourceName()</ins>
+              </td>
+              <td>
+                <p><ins>For Module Records that implement a normal completion for GetModuleSource(), returns a String corresponding to the source record type to be used as the strongly branded return value of the @@toStringTag getter on %AbstractModuleSource%.</ins></p>
+                <p><ins>For Module Records that do not have a source representation, GetModuleSourceName() is never called.</ins></p>
+              </td>
+            </tr>
           </table>
         </emu-table>
       </emu-clause>
@@ -2024,6 +2033,23 @@ contributors: Luca Casonato, Guy Bedford, Nicolò Ribaudo
         <h1>%AbstractModuleSource%.prototype.constructor</h1>
         <p>The initial value of %AbstractModuleSource%`.prototype.constructor` is %AbstractModuleSource%.</p>
       </emu-clause>
+
+      <emu-clause id="sec-get-%abstractmodulesource%.prototype.@@tostringtag">
+        <h1>get %AbstractModuleSource%.prototype [ @@toStringTag ]</h1>
+        <p>%AbstractModuleSource%.prototype `[@@toStringTag]` is an accessor property whose set accessor function is *undefined*. Its get accessor function performs the following steps when called:</p>
+        <emu-alg>
+          1. Let _O_ be the *this* value.
+          1. If _O_ is not an Object, return *undefined*.
+          1. Let _sourceRecordResult_ be Completion(HostGetModuleSourceRecord(_O_)).
+          1. If _sourceRecordResult_ is an abrupt completion, return *undefined*.
+          1. Let _sourceRecord_ be ! _sourceRecordResult_.
+          1. Let _name_ be ! _sourceRecordResult_.getModuleSourceName().
+          1. Assert: _name_ is a String.
+          1. Return _name_.
+        </emu-alg>
+        <p>This property has the attributes { [[Enumerable]]: *false*, [[Configurable]]: *true* }.</p>
+        <p>The initial value of the *"name"* property of this function is *"get [Symbol.toStringTag]"*.</p>
+      </emu-clause>
     </emu-clause>
   </emu-clause>
 </emu-clause>