wpm-config.json (WP-Multilang). UNDERSCORE!

wpm-config.json

{
  "post_types": {
    "post_type_name": {}
  },
  "taxonomies": {
    "tax_name": {}
  },
  "post_fields": {
    "_genesis_title": {}, // The SEO Framework
    "_genesis_description": {}, // The SEO Framework
    "_open_graph_title": {}, // The SEO Framework
    "_open_graph_description": {}, // The SEO Framework
    "_twitter_title": {}, // The SEO Framework
    "_twitter_description": {}, // The SEO Framework
    "_custom_field_name": {},
    "_custom_field_group_name": {
      "wpm_each": {
        "_custom_field_in_group": {}
      }
    }
  },
  "term_fields": {
    "_custom_field_name": {},
    "_custom_field_group_name": {
      "wpm_each": {
        "_custom_field_in_group": {}
      }
    }
  }
}