XLSR-Wav2Vec2 is a speech model that accepts a float array corresponding to the raw waveform of the speech signal.
XLSR-Wav2Vec2 model was trained using connectionist temporal classification (CTC) so the model output has to be
  decoded using [Wav2Vec2CTCTokenizer].

XLSR-Wav2Vec2's architecture is based on the Wav2Vec2 model, so one can refer to Wav2Vec2's documentation page.