https://youtu.be/L7XIFC2SawY?si=qN7TNxZi-P05uXVa
It's basically a custom 3D multithreaded OSM renderer, and the assets are a custom binary format. Uses very little network bandwidth.
Hoping to have an update this year that shows the updated graphics. I wrote a UI framework to improve my productivity (live hot reloading of UI components written with HTML with one way data binding. I had to do this because the game is gonna have so many UIs and I got tired of writing them in Java 8 style Java. Soon I can resume work on the game after sidewaysdata.com is doneish (also using the UI library to build the desktop/mobile timing application).
The "many UI" problem is large in Rust. Egui needs far too much Rust code per dialog box. Someone was working on a generator, but I haven't looked in on that project in a while.