Borland TurboVision (the PC text mode windowing UI used in Turbo Pascal/C++) has been open-sourced and updated to work seamlessly on Linux and with Unicode:
https://github.com/magiblot/tvision
It’s all in C++, though if someone hasn’t wrapped it in bindings for Python/Rust/&c. yet, surely they will
Hacker gets annoyed at Amazon’s Kindle apps, reverse-engineers the Kindle web reader’s protocol (which basically sends each page as a set of glyphs in a deliberately broken variant of SVG). Such obscurity, much security.