I agree https://bugs.python.org/issue31197 is orthogonal - refactoring the current logic is useful regardless of what we do at the object attribute layer.

Regarding __delegated_to__/__returns_to__, the reason I like *not* having "async" in the attribute names is that generators are actually used as a synchronous construct (via synchronous for loops and next() calls), even though they technically define an asynchronous operation from the interpreter's point of view.

The reason I like omitting "call" (or "calls") from the name is that even though "yield from" and "await" are both sometimes described as providing syntax for asynchronous calls, that terminology is really only defensible for "await" - PEP 380 describes the "yield from" operation as delegating to a subgenerator, and I think that's a better way of framing the general concept.