API reference index page doesn't have links to all API documentation

The API reference index page, which is what one gets when clicking the "API Reference" link on the top bar of the documentation, lists the top level section of the documentation of each module, instead of its actual API reference.

The left hand "section navigation" column provides what I think one would expect an API reference index page to look like. I'm not sure where the inconsistency lies but it would be nice if we could resolve it.

h/t @rdicosmo