Audio of Nirvana live in Madison surfaces

Someone who goes by "Greg D" has posted some audio from Nirvana's gig here in Madison at O'Cayz Corral on 7 July 1989. Just one song prefaced by what sounds like an early instrumental take of "Even In His Youth". I was told by the sound guy who did one of their 2 shows here - the other being 6 April 1990 at Club Underground -  but I cannot remember which, that he had intended to record it but forgot to push the record button after, um, partaking. Oops.