Return 404 for non html files

backend/open_webui/main.py

@@ -330,7 +330,13 @@ class SPAStaticFiles(StaticFiles):
             return await super().get_response(path, scope)
         except (HTTPException, StarletteHTTPException) as ex:
             if ex.status_code == 404:
-                return await super().get_response("index.html", scope)
+                if path.endswith(".html"):
+                    response = await super().get_response("index.html", scope)
+                    response.status_code = 200
+                    return response
+                else:
+                    # Return 404 for non-HTML files
+                    raise ex
             else:
                 raise ex