src/transformers/tokenization_utils.py/PreTrainedTokenizer/get_added_vocab
class PreTrainedTokenizer:    def get_added_vocab(self) -> Dict[str, int]:
        """
        Returns the added tokens in the vocabulary as a dictionary of token to index.

        Returns:
            `Dict[str, int]`: The added tokens.
        """
        return self.added_tokens_encoder