I want to document my API with sphinx/myst/autodoc2.

According to https://myst-parser.readthedocs.io/en/latest/syntax/code_and_apis.html#sphinx-autodoc2, there is an "auto_mode" with a link "as shown API Reference."
But the API reference IMHO is only the API of MYST itself, and does not contain any auto_mode.

A search for "auto_mode" references only the one link (see before), and it is never explained how to use the auto_mode...

Is this completely missing/forgotten? Does auto_mode exist? If I search the whole Github repo for "auto_mode", I only get one line:

So is this not implemented yet?