Björk sang Schönberg's "Pierrot Lunaire" and only 1:14 of recordings are extant. This makes me sad. http://tinyurl.com/2g899nd
It makes me sad too! The quality is just awful, the audio equivalent of your phone taking a picture of the inside of your pocket. But the site is almost like a case file, trying to track down scraps of the past and figure out what exactly happened there in 1996.
Björk - Mondestrunken
Björk - Galgenlied
I myself have a lost hard drive filled with Björk mysteries; in the filesharing heyday of the early aughts I downloaded anything I could get my hands on. I have mixes never seen before or since, and recordings I have no clue the origins of. Though I am sad that there may be no record of this performance, in our increasingly pinned-to-the-corkboard world, I do appreciate some mystery.