Apple loops format

When I use an imported midi file and create a user Apple Loop using that file and a Logic software instrument, in what format does Logic save that? It appears in the loop browser as a green (software instrument) loop. But, when I went to find one to delete it after making a mistake, I found an .aif extension attached to it. If that's an aiff file, then it's taking a lot more room than I thought on my hard drive.