i've seen at least one person talk about it, and two people discussing it. These kinds of things tend to be very hit or miss, some people get imploded, others see literally nothing happen. And a few will have very weird minor breakages.
One nice thing about KDE compared to most of the other DEs is that the window manager (kwin) is separate from the underlying components, and it can be replaced!
You get i3 for tiling window management but you still get to use KDE's system settings to do configuration like display settings, themes keyboard shortcuts, etc, just like you did before. You can also pick and choose which parts of the KDE desktop you want to keep (menu, krunner, etc)
Since i3 is just a window manager and is lacking all of that system level stuff it really rounds out i3 to feel like a full DE instead of having to piece together other tools to do those things.
i've heard about this, never looked into it because it was about the same effort as just using a dynamic tiling WM anyway. Sounds like it would only be funkier if i did replace it.
even then 90% of what has annoyed me since switching is theming, which is pretty self contained already. So that's easy enough to fix, except for QT theming because it just has to break everything that exists.
But yeah, it's cool having this be a thing in linux for sure.