The `mip_era` keyword in [cordex.cordex_domain](https://py-cordex.readthedocs.io/en/latest/generated/cordex.cordex_domain.html#cordex-cordex-domain) should become part of the table index to distinguish between CMIP5/CMIP6 domains. See also: * https://github.com/WCRP-CORDEX/domain-tables/issues/6