--- a/js/src/doc/Debugger/Debugger.Source.md
+++ b/js/src/doc/Debugger/Debugger.Source.md
@@ -117,22 +117,27 @@ from its prototype:
     source, then this property's value is that URL. Otherwise, this is `null`.
 
     (On the web, the translator may provide the source map URL in a
     specially formatted comment in the JavaScript source code, or via a
     header in the HTTP reply that carried the generated JavaScript.)
 
     This property is writable, so you can change the source map URL by
     setting it. All Debugger.Source objects referencing the same
-    source will see the change. Setting an empty string has no affect
+    source will see the change. Setting an empty string has no effect
     and will not change existing value.
 
     **If the instance refers to WebAssembly code**, `null`. Attempts to write
     to this property throw a `TypeError`.
 
+`displayURL`
+:   If the script had a special `//# sourceURL` comment, as described in
+    the source maps specification, then this property's value holds
+    the string that was given.  Otherwise, this is `null`.
+
 `element`
 :   The [`Debugger.Object`][object] instance referring to the DOM element to which
     this source code belongs, if any, or `undefined` if it belongs to no DOM
     element. Source belongs to a DOM element in the following cases:
 
     * Source belongs to a `<script>` element if it is the element's text
       content (that is, it is written out as the body of the `<script>`
       element in the markup text), or is the source document referenced by its