What is your issue?

I noticed that the docstrings of the aggregation methods are mostly written in the same style, e.g.: "Reduce this Dataset's data by applying xy along some dimension(s).". Let's say a user is interested in calculating the variance and searches for the appropriate method. Neither xarray.DataArray.var nor xarray.Dataset.var will be returned (see here), because "variance" is not mentioned at all in the docstrings. Same problem exists for other methods like .std, .prod, .cumsum, .cumprod, and probably others.

#6793 is related, but I guess it already has enough tasks.