Lebaran or Eid al-Fitri without ketupat (rice steamed in diamond shape packet and wrap in coconut leaves) is like cooking without salt, so enthusiastic Indonesia moslem in celebrating Eid al-Fitr by avoiding ketupat cooking in their homes, so that the houses celebrating Eid al-Fitr without ketupat are less genuine.
Ketupat is a typical Southeast Asian food (wikipedia)
Typical foods that use ketupat, among others kupat tahu (Sunda), katupat kandangan (Banjar), Grabag (Magelang), kupat glabet (Tegal City), coto makassar (Makassar
which can be served with ketupat or lontong. Ketupat can also be served to accompany satai, satai, although lontong is more common.
Here are 5 photos of packages of ketupat
Below are photos of Ketupat from Muhaerin’s posting