"??" meaning in Français

{
  "categories": [
    {
      "kind": "other",
      "name": "Palindromes en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Symboles en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Français",
      "orig": "français",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Français",
  "lang_code": "fr",
  "pos": "symbol",
  "pos_title": "Symbole",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Signes de ponctuation en français",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Termes populaires en français",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Indique que la phrase terminée est un doute fort."
      ],
      "id": "fr-??-fr-symbol-HHjiJg5K",
      "raw_tags": [
        "Populaire"
      ],
      "topics": [
        "typography"
      ]
    }
  ],
  "word": "??"
}

{
  "categories": [
    "Palindromes en français",
    "Symboles en français",
    "français"
  ],
  "lang": "Français",
  "lang_code": "fr",
  "pos": "symbol",
  "pos_title": "Symbole",
  "senses": [
    {
      "categories": [
        "Signes de ponctuation en français",
        "Termes populaires en français"
      ],
      "glosses": [
        "Indique que la phrase terminée est un doute fort."
      ],
      "raw_tags": [
        "Populaire"
      ],
      "topics": [
        "typography"
      ]
    }
  ],
  "word": "??"
}