What large Berber confederation, principally inhabiting the Sahara desert, also has an annual festival showcasing their traditional music?
Festival au Désert: The Festival au désert ("Festival in the Desert") is an annual concert in Mali, showcasing traditional Tuareg music as well as music from around the world. Tuareg people: The Tuareg people ( ; also spelled Twareg or Touareg; endonym "Kel Tamasheq", "Kel Tagelmust") are a large Berber ethnic confederation. Tuareg people:  They principally inhabit the Sahara desert, in a vast area stretching from far southwestern Libya to southern Algeria, Niger, Mali and Burkina Faso.
Tuareg people