Multiindex after stacking chain, draw for sbc.prior inferencedata

[hyunjimoon]

1. After upgrading to the newest arviz, adding create_index = False during stack, (chain, draw) still remains in the produced dataset (sbc.prior).
2. why don't we have region as coordinate?

In specific, I am having difficulty understanding what the function of .mean('prior_draw') in this setting. When I add this command, things seem much better (second figure below).