I brought this topic up on python-ideas and both Nick Coghlan and MA Lemburg suggested the abc module like Yury did. So the proposal becomes to put syntax-related ABCs into the abc module and domain-specific ones in their respective stdlib modules.

Nick suggested the following ABCs get pulled out of collections.abc and put into the abc module:

    Callable - function calls
    Iterable - for loops, comprehensions
    Iterator - for loops, comprehensions
    Generator - generators, generator expressions
    Awaitable - await expressions
    Coroutine - async def
    AsyncIterable - async for
    AsyncIterator  - async for