great question! the output notebooks generated by NotebookRunner are uploaded to S3. If you want to aggregate results, you have a few options.
1. download the output notebooks from S3 and extract the notebooks using our sklearn-evaluation tool https://sklearn-evaluation.readthedocs.io/en/latest/user_guide/NotebookCollection.html
2. create a final task in your pipeline that aggregates the notebooks with sklearn-evaluation. then download the final notebook
3. add mlflow or any other experiment tracker to log the results. we have an example here: https://github.com/ploomber/projects/tree/master/templates/mlflow
does this help?