The Fly-RRF-E3 has been replaced by the Fly-E3-V2 https://github.com/Mellow-3D/fly-e3-v2
RRF information can be found here https://teamgloomy.github.io/fly_e3_general.html
For Klipper support please join this Discord Channel https://discord.gg/zAung88zbK
For RRF support please join this Discord Channel https://discord.gg/uS97Qs7