list available previewers, explain where they come from #10506

Author: pdurbin

doc/sphinx-guides/source/container/running/demo.rst

@@ -195,7 +195,23 @@ Dataverse supports multiple Persistent ID (PID) providers. The ``compose.yml`` f
 File Previewers
 +++++++++++++++
 
-By default, all available file previewers are enabled (see :ref:`file-previews` in the User Guide for details). If you want to specify fewer previewers, you can edit the ``compose.yml`` file. Look for the "INCLUDE_PREVIEWERS" line.
+By default, all available file previewers are enabled (see :ref:`file-previews` in the User Guide for details). Specifically, we enable all the previewers that are available in the `trivadis/dataverse-previewers-provider <https://hub.docker.com/r/trivadis/dataverse-previewers-provider>`_ image (`code <https://github.com/TrivadisPF/docker-register-dataverse-previewers>`_). You can run the following command to see a list of available previewers:
+
+``docker run trivadis/dataverse-deploy-previewers:latest previewers``
+
+You should expect to see output like this:
+
+.. code-block:: text
+
+        name     description
+        ----------------------------
+        text     Read the text file.
+        html     View the html file.
+        ...
+
+If you want to specify fewer previewers, you can edit the ``compose.yml`` file. Uncomment "INCLUDE_PREVIEWERS" and list the previewers you want, separated by commas, like this:
+
+``INCLUDE_PREVIEWERS=text,html,pdf,csv``
 
 Next Steps
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