"Check Tempo" in Media Bay not in the manual

Since it’s not mentioned in the manual (at least I wasn’t able to find it), what is “Check Tempo” in the Media Bay supposed to do? Set the tempo for an audio file? If so, it seemingly doesn’t work. Or does it only read tempo information that is already in the file?

It would be nice if this would finally find its way into the manual to make me stop scratching my head.