diff --git a/validation/validate-mmcif-file.py b/validation/validate-mmcif-file.py
index 252c334281008070caba6eafa2afaad2f1a9cb75..f5aa7bfabe0d42b9a4b72d45233eea46fa35b1c4 100755
--- a/validation/validate-mmcif-file.py
+++ b/validation/validate-mmcif-file.py
@@ -297,6 +297,9 @@ def _get_associated_files(model_cif_file, assoc_dir):
                 )
             if row[idxs["file_format"]] != "cif":
                 continue
+            # this should be easy to make reading URLs, using
+            # _get_assoc_obj(row[idxs["file_url"]], assoc_dir) but for now
+            # I have not seen the use case (no web server at hand for testing)
             data = _read_mmcif(os.path.join(assoc_dir, row[idxs["file_url"]]))
             assoc_files.append((data, row[idxs["entry_id"]]))
         # make sure entry_id is matching in associated file!