The top results for Google searches like "numpy subclass ndarray" point toward the 1.12.0 docs. Three requests/suggestions.

1. A prominent "There is a newer version" link to the 1.13.0 docs.

2. The 1.12.0 page linked above directs the user to use __numpy_ufunc__ for subclassing. I'm not entirely clear on the timeline in ENH: Add __array_ufunc__ #8247, but I couldn't make numpy_ufunc work with 1.12.0, so it isn't obvious whether the doc is accurate or (much more likely) I'm screwing up.

3. A non-toy example for numpy_ufunc and/or array_ufunc, ideally demonstrating the tie-ins or use cases for the array_prepare/array_finalize/...