I expect it should eventually be added to tkinter. But I also think it
might be worthwhile to first develop it as a 3rd party package on
PyPI, to see if it can actually be done well enough to put it in the
stdlib.

I guess a demo app should be part of the project; the demo should show
that some independently developed asyncio code (perhaps derived from
examples/crawl.py in the asyncio repo) can run while also maintaining
a UI built using Tkinter responsive. Ideally there would also be a
demonstration of how the UI and the crawl code interact. And no
threads.