A version of RTKLIB optimized for low cost GNSS receivers, especially u-blox receivers. It is based on RTKLIB 2.4.3 and is kept reasonably closely synced to that branch. This software is provided “AS IS” without any warranties of any kind so please be careful, especially if using it in any kind of real-time application.
The Rinex 3.04 spec names this '8I', so '8L' appears to be an error. https://github.com/rtklibexplorer/RTKLIB/issues/411