diff --git a/extension/Source/core/Save.php b/extension/Source/core/Save.php
index a578d4a75b4f9ddc769a0d598a1e5a2a0c8fcb40..9df3c42d02f44e3ecc0ba40a22722df3c2dbf8cd 100644
--- a/extension/Source/core/Save.php
+++ b/extension/Source/core/Save.php
@@ -669,6 +669,7 @@ class Save {
             $importNamedSheetsOnly = explode(',', $formElement[FE_IMPORT_NAMED_SHEETS_ONLY]);
         }
 
+        // Check for keywords which needs an explicit given document type.
         if ($formElement[FE_IMPORT_TYPE] === FE_IMPORT_TYPE_AUTO) {
 
             $list = [FE_IMPORT_LIST_SHEET_NAMES, FE_IMPORT_READ_DATA_ONLY, FE_IMPORT_LIST_SHEET_NAMES];