I had no idea this even existed until I noticed it on HBO yesterday. It was very good, lots of home videos of Courtney and Kurt.
http://www.imdb.com/title/tt4229236/
I also heard they are supposed to be releasing a soundtrack album of Kurt just basically singing and fiddling with the guitar. I really like this Beatles cover I heard on the film.
https://www.youtube.com/watch?v=xdcA_ozN17Q