This is a short sound byte which has not been treated in any way. The waveform shows the sound, which is five seconds of male speech, as it was recorded.
The image below shows the same sound after limiting has been applied to it to 'hold back' the high level peaks of the sound without affecting the quieter parts. You will see that the basic waveshape is the same but larger excursions away from the centre line are less dramatic. This file could now be amplified without distortion because the peaks of the sound have been reduced in level. If your sound editing software allows you to see a long selection of the audio waveform then you can recognise a strongly limited file by the flat look of the top and bottom of the waveform. This is especially apparent when you look at a several minutes of waveform on the screen at once.