Yeah found this :
Within the NOAA model unification effort, the RRFS represents the evolution of the NAM, RAP, HRRR, and HREF systems to a new unified deterministic and ensemble storm-scale system. This new system is targeted for initial operational implementation in late 2024 as a planned replacement for the NAMnest, HRRR, HiResWindows, and HREF. While the standalone regional (SAR) FV3 model is being developed for convection-allowing forecasting of a limited area (CONUS), other possible components of the RRFS are being tested now in the experimental, WRF-based High-Resolution Rapid Refresh Ensemble (HRRRE).