group of people gathered in a street in Yogyakarta, Indonesia, located at -7

group of people gathered in a street in Yogyakarta, Indonesia, located at -7.783 latitude and 110.367 longitude. The street is paved with grey cobblestone. The group of people are standing in front of a large flatbed truck that is decorated with red and white flags, sound equipment, and a banner that reads "SERBUK" in Indonesian. Several people are standing on the truck, some of them holding microphones. The people on the ground are mostly men, and some of them are holding banners and flags. The people on the ground are wearing casual clothes and some are wearing safety vests. The sky is overcast and there are buildings visible in the background. There is a large white banner lying on the ground in front of the truck.