Where does Unity saves importer converted file versions?

If, say, I import an audio file on the assets forlder, or an image for that matter, and I select on the importer settings for Unity to compress the file and hit apply, the importer processes the file and saves an alternative version of that file in order to have it ready and use it while the game is running.

Where can I find this alternative compressed version file?

Also, can I somehow access those files?

The reason is that I need to run some quality tests in order to approve my workflow.

Thanks in advance!