YAC is a defined infrastructure component of the German natESM system.
YAC 1.2.0 has been developed by DKRZ and the Max Planck Institute for Meteorology (MPI-M) to realize an efficient coupling of Earth system model components. To meet the special needs of the Icosahedral Nonhydrostatic general circulation model (ICON), YAC was developed. YAC offers flexible coupling of physical fields defined on different types of grids on the sphere. All supported grids can be combined with any of the interpolations supported.
The software is open-source (see license).
More information, publications, configurations and members of the team about YAC here and short presentation.
If you want to get started, the software is available on GitLab, also with a Graphical User Interface. The latest documentation is filed here, which includes also a Initalisation section.