What Is Balkan Brass?

For readers entirely unfamiliar with the tradition, this is a great place to start.
Balkan Brass is a style of music originating in the Balkan region in Europe, including Croatia, Bosnia and Herzegovina, Montenegro, Albania, North Macedonia, Kosovo, Serbia, Bulgaria and Romania. Occasionally, Moldavia, Greece, and continental Turkey are added to the list of Balkan Brass' origins.
The Romani minority community in Europe is the primary origin of this style of music. It must be acknowledged that their musical style has been influenced through cultural exchange with other communities in the region, such as the Muslim and Jewish peoples in Europe.
The music is a fusion of military and folk influences. After the liberation of Serbia in the early 1800s, the military brass performance traditions in the region were inevitably 'brought home,' and people began performing their own cultural music and folk tunes using variations of trumpets, brass ensembles, and percussion.
Balkan brass ensembles include wide variations of brass instruments including:

• Fugelhorn, trumpet, and cornet
• Trombone, valve trombone, alto horns, and euphonium
• Tenor horns, tenor tubas, and Wagner tubas
• Tuba, sousaphone, or Helicon

In addition, their percussion sections include snare and bass drums, as well as the davul, a large traditional Middle Eastern drum which produces a bassy sound, and is struck with mallets and other implements to produce different sounds.

Sources:
Balkan brass wikipedia page
Balkan Trafik festival page