diff --git a/spec/index.bs b/spec/index.bs
index fd14ebe01f..3a8a29e2c6 100644
--- a/spec/index.bs
+++ b/spec/index.bs
@@ -2231,9 +2231,14 @@ conditions.
 <script type=idl>
 dictionary GPUShaderModuleDescriptor : GPUObjectDescriptorBase {
     required DOMString code;
+    object sourceMap;
 };
 </script>
 
+{{GPUShaderModuleDescriptor/sourceMap}}, if defined, MAY be interpreted as a
+source-map-v3 format. (https://sourcemaps.info/spec.html)
+Source maps are optional, but serve as a standardized way to support dev-tool
+integration such as source-language debugging.
 
 # Pipelines # {#pipelines}