I know, I know, no plans. But I will humbly put forth that I've been using Aquamail for years on Android. At least 5 years, maybe even 10 years ... (How old is Aquamail?)
Yahoo email just changed their web interface, again, and I am not a fan. So I tried Em Client. Nope. It hogs hard drive space, and I can't figure out why, but there was an email I sent to myself that Aquamail showed, Yahoo email on the web showed, but Em Client did not, no matter how I tried to sync them, restarted it, and it wasn't in the Trash folder either. (Yes, I will try Thunderbird next.)
Just very plainly: Aquamail rules.

And I would *love* a Windows version ... 👍👍👍