special_tokens_map.json

{
  "pad_token": {
    "content": "_",
    "lstrip": false,
    "normalized": false,
    "rstrip": false,
    "single_word": false
  },
  "unk_token": {
    "content": "UNK",
    "lstrip": false,
    "normalized": false,
    "rstrip": false,
    "single_word": false
  }
}