"BR" meaning in Conventions internationales

{
  "categories": [
    {
      "kind": "other",
      "name": "Polymères",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Symboles en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Conventions internationales",
      "orig": "conventions internationales",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole 1",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en conventions internationales de l’automobile",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Signe distinctif en trafic international des véhicules automobiles immatriculés au Brésil, prescrit dans le cadre de la Convention sur la circulation routière de Genève de 1949 et de la Convention sur la signalisation routière de Vienne de 1968."
      ],
      "id": "fr-BR-conv-symbol-yNIaep1Z",
      "topics": [
        "automobile"
      ]
    },
    {
      "glosses": [
        "Code ISO 1629 du polybutadiène (butadiene rubber)."
      ],
      "id": "fr-BR-conv-symbol-E8MCrMZe",
      "topics": [
        "chemistry"
      ]
    },
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en conventions internationales de la géographie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Code ISO 3166-1 (alpha-2) du Brésil."
      ],
      "id": "fr-BR-conv-symbol-TDMRblci",
      "topics": [
        "geography"
      ]
    }
  ],
  "tags": [
    "invariable"
  ],
  "word": "BR"
}

{
  "categories": [
    "Polymères",
    "Symboles en conventions internationales",
    "conventions internationales"
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole 1",
  "senses": [
    {
      "categories": [
        "Lexique en conventions internationales de l’automobile"
      ],
      "glosses": [
        "Signe distinctif en trafic international des véhicules automobiles immatriculés au Brésil, prescrit dans le cadre de la Convention sur la circulation routière de Genève de 1949 et de la Convention sur la signalisation routière de Vienne de 1968."
      ],
      "topics": [
        "automobile"
      ]
    },
    {
      "glosses": [
        "Code ISO 1629 du polybutadiène (butadiene rubber)."
      ],
      "topics": [
        "chemistry"
      ]
    },
    {
      "categories": [
        "Lexique en conventions internationales de la géographie"
      ],
      "glosses": [
        "Code ISO 3166-1 (alpha-2) du Brésil."
      ],
      "topics": [
        "geography"
      ]
    }
  ],
  "tags": [
    "invariable"
  ],
  "word": "BR"
}