I'm still confused by this not being cross-platform. It's made in Rust; basically every graphics library is cross platform out of the box, and so is all the file IO stuff. There will be some specialist OS api stuff in places but surely it can't be much.
For once this comment isn't even snark. I acknowledge my ignorance and wonder if someone could explain why the cost is bigger than I think?
Perhaps it's setting up CI and packaging for other platforms? Maybe they want human QA on every release? Maybe the APIs for slick OS integration are more complicated than I realise? (e.g. putting UI in the taskbar)