``spec`` that will be passed to the ``fetch()`` method. `For example, see the ZenodoProvider detect method <https://github.com/jupyterhub/repo2docker/pull/693/files#diff-a96fcf624176b06e21c3ef7f6f6a425bR31>`_.
`For example, see the ZenodoProvider fetch method <https://github.com/jupyterhub/repo2docker/pull/693/files#diff-a96fcf624176b06e21c3ef7f6f6a425bR57>`_.