No problem. There's some issues with it right now, but feel free to give it some testing at https://github.com/swaywm/sway/pull/4570.

It has been an interesting exercise so far, and frankly a quite pleasant one. Rather than autotools or CMake, many of these projects are using Meson, which is just so much nicer. I also really have learned to appreciate Sway WM's code, which I personally think is quite nice now, after having worked with it (though, admittedly, the ease of segfaulting does make you long for something like Rust.)

Thanks again! I might just try this out. Just one small thing: I was expecting this to be a wlroots PR. Why would it be sway-specific?

wlroots already has first-class drawing tablet support, but the "process input events" parts and the "dispatch input events to clients" parts are separated and it's up to the compositor to connect them in the ways they best see fit.