I've always found it confusing that frame.representation points to a class of the representation. I propose we deprecate this attribute in favor of frame.representation_cls.

I've already implemented the new attribute in #6219 (which supports and can handle either .representation or .representation_cls), but we should decide if I should put a deprecation warning in there for v2.0 or wait. My vote is that we put it in v2.0

Milestoned for 2.0 so we make a decision.

cc @eteq @mhvk @taldcroft