Creating an Atlassian Connect report module for a board

These docs describe how to define a report in your Atlassian Connect plugin for JIRA:

However these reports are created within the context of the entire project rather than the context of a specific board (even for reports with a reportCategory of ‘agile’ or ‘AGILE’).

Only project.key and are available to the add-on. When I add to the url in the descriptor, it is left undefined.

How can I create a report for a board, consistent with most of the existing reports under the “Agile” category?