Singer recorded acoustic version of Nirvana classic at home on four-track recorder in 1988
Untitled song culls from cassette likely recorded around making of 'Nevermind'
"I didn't realize it was such a historical thing," 19-year-old Maggie Poukkula says. "I thought they were just cool pictures…
"The dark stuff at the end I think would bum me out," singer says
Kurt Cobain 'was a master of jerking your chain,' explains Buzz Osborne.
HBO offers in-depth look at the upcoming documentary with never-before-seen home movies and family photos
Docs on Nina Simone and Scientology are also slated for the 2015 festival, along with new films staring James Franco,…
