A few months ago, I decided to make the code source-available[2] in part because I like the idea of my users being able to see the code they're running and in part because I want to showcase that one can build serious applications with Racket. The app also has a somewhat unusual architecture: the "backend" (the "core" folder) is written in Racket, the Mac "frontend" (the "FranzCocoa" folder) is Swift + Cocoa/SwiftUI[3, 4], and the two sides communicate over pipes. The Windows and Linux versions (the "FranzCross" folder) reuse the Racket core and implement the frontend using a wrapper around Racket's cross-platform GUI toolkit[5, 6]. My goal is to eventually port the frontend for the latter two platforms to use their native toolkits directly as well (see [3] for some more details re. Windows).
Happy to answer any questions!
[1]: https://defn.io/2022/11/20/ann-franz/
[2]: https://defn.io/2023/08/10/ann-franz-source-available/
[3]: https://defn.io/2023/03/19/racketfest-talk-2023/
[4]: https://defn.io/2022/08/21/swiftui-plus-racket-screencast/