Docs mention non-existent doc/source/api.rst
E.g. in doc/source/development/contributing.rst it says:
> * Our API documentation in ``doc/source/api.rst`` houses the auto-generated
>   documentation from the docstrings. For classes, there are a few subtleties
>   around controlling which methods and attributes have pages auto-generated.
> 

There's a few other mentions of it elsewhere
