> In formulating my question for the list, it occurred to me that while asynccontextmanager doesn't need to depend on asyncio, the AsyncExitStack proposed in issue 29302 likely will, which pushes me towards favouring the `asyncio.contextlib.asynccontextmanager` approach.

As I said in [1], I think asynccontextmanager and AsyncExitStack should be framework agnostic and thus stay in the top level contextlib package.

IMO AsyncExitStack should not be dependent on asyncio, and if it is it means we would need to tweak its design to make it not to.  I'll take a look at the other issue to see if I can help.

[1] https://mail.python.org/pipermail/python-dev/2017-March/147505.html