diff --git a/c-sharp/Projects/ParatextProjectStorageInterpreter.cs b/c-sharp/Projects/ParatextProjectStorageInterpreter.cs
index c4fcc8c9ee..3a32ccf407 100644
--- a/c-sharp/Projects/ParatextProjectStorageInterpreter.cs
+++ b/c-sharp/Projects/ParatextProjectStorageInterpreter.cs
@@ -133,7 +133,7 @@ public override ResponseToRequest SetProjectData(ProjectDataScope scope, string
                         );
                     }
                 );
-                return ResponseToRequest.Succeeded($"chapter:{verseRef}");
+                return ResponseToRequest.Succeeded($"{Chapter}:{verseRef}");
             default:
                 return ResponseToRequest.Failed($"Unknown data type: {scope.DataType}");
         }
@@ -184,7 +184,7 @@ public override ResponseToRequest SetExtensionData(ProjectDataScope scope, strin
                     textWriter.Flush();
                 }
             );
-            return ResponseToRequest.Succeeded($"extensions:{scope.ExtensionName}");
+            return ResponseToRequest.Succeeded($"ExtensionData:{scope.ExtensionName}");
         }
         catch (Exception e)
         {
diff --git a/lib/papi-dts/papi.d.ts b/lib/papi-dts/papi.d.ts
index 2c852f0f62..a583977103 100644
--- a/lib/papi-dts/papi.d.ts
+++ b/lib/papi-dts/papi.d.ts
@@ -1492,7 +1492,17 @@ declare module 'shared/models/project-data-provider.model' {
   import type { DataProviderDataType } from 'shared/models/data-provider.model';
   /** Indicates to a PDP what extension data is being referenced */
   export type ExtensionDataScope = {
+    /** Name of an extension as provided in its manifest */
     extensionName: string;
+    /** Name of a unique partition or segment of data within the extension
+     * Some examples include (but are not limited to):
+     *  - name of an important data structure that is maintained in a project
+     *  - name of a downloaded data set that is being cached
+     *  - name of a resource created by a user that should be maintained in a project
+     *
+     * This is the smallest level of granularity provided by a PDP for accessing extension data.
+     * There is no way to get or set just a portion of data identified by a single dataQualifier value.
+     * */
     dataQualifier: string;
   };
   /** All Project Data Provider data types must extend from this */