BUG: numpy needs to override the sphinx autosummary class.rst

I am not sure of the interactions between all the pieces, but here my understanding:

• numpy has a class.rst template that extends the one in sphinx's autosummary extension. It adds a toctree option to a nested autosummary directive (nested under a HACK directive)
• During the parse phase, sphinx adds the toctree contents to the documentation, since this is all done with regex and it doesn't care there are nested directives
• Since sphinx ignores nested directives during output processing, the toctree is not generated
• As far as sphinx is concerned, the generated documents are not in any toctree, so we added an orphan tag to them in additional templates in numpy to avoid a warning.

So why do we need the toctree in the template in the first place? Removing the numpy class.rst seems to produce problematic documentation. Is this a numpydoc or sphinx problem or just a feature?

Start by inspecting numpydoc's numpy class.rst template and the corresponding Sphinx autosummary template, then reproduce the documentation build described in the issue. Trace how the nested autosummary, toctree, and orphan directives are handled. Done means determining whether this belongs in numpydoc or Sphinx and documenting or implementing the agreed fix.