I'm working on adding array API support in scipy.stats (scipy/scipy#20544) and one of the the things I'll need is a quantile function. If there is some support for this idea, I'll convert this issue into a proper proposal.

Looks like there is already wide support:

• numpy.quantile
• torch.quantile
• cupy.quantile
• jax.numpy.quantile
• dask.dataframe.DataFrame.quantile
• tfp.stats.quantiles
• xarray.DataArray.quantile

Previous discussions (not much):

• Proposal to standardize basic statistical functions #10 (comment)
• Behavior of reductions on empty arrays should be specified #232 (comment)

There are many conventions for calculating quantiles. Only a few methods would be required by the standard, and if choice of a default is too contentious, perhaps the array-API can consider method to be a required keyword argument, and libraries would be welcome to keep their own default.