From the FAQ[1], it sounds like neither X11 nor Wayland are currently supported.
[1]: https://www.redox-os.org/faq/#what-programs-can-redox-run
[1]: https://www.redox-os.org/faq/#what-programs-can-redox-run
https://doc.redox-os.org/book/ch04-09-graphics-windowing.htm...