diff --git a/backend/pashub_fetcher/core_files.py b/backend/pashub_fetcher/core_files.py
index 050dde27..07297653 100644
--- a/backend/pashub_fetcher/core_files.py
+++ b/backend/pashub_fetcher/core_files.py
@@ -65,6 +65,8 @@ _MATCHERS: list[tuple[Callable[[str], bool], str]] = [
 def core_file_for(
     filename: str, evidence_category: Optional[str] = None
 ) -> Optional[CoreFiles]:
+    if evidence_category is not None and evidence_category.lower() == "retrofit design":
+        return CoreFiles.RETROFIT_DESIGN_DOC
     raise NotImplementedError