Emanuel, have you seen <https://docs.python.org/devguide/documenting.html#building-the-documentation>? From my experience, install Sphinx, and then “make -C Doc/ html”.

About the patch, I think the “.. note” boxes should be intended under the NotImplementedError heading. The current box looks wrong sandwiched between NotImplemnted and Ellipsis.

(Personally I think “Note” boxes are an annoying distraction anyway, and should normally be written into the surrounding text. In this case “Note that” inside a “Note” box seems doubly redundant. But other people seem to like them, so I try to resist complaining :)