Like opera buffa it used contemporary settings and characters, comic or at least satiric plots (Max Brand's Maschinist Hopkins is a sole tragic example) and aimed at musical accessibility.
[1][2] Other composers are Paul Hindemith (Hin und zurück, 1927, Neues vom Tage, 1929), Wilhelm Grosz (Achtung!
to a libretto by Bela Balazs), plus Weill's Der Zar lässt sich photographieren (1928) and Die Bürgschaft (1932).
At the possible instigation of Krenek, the American George Antheil also wrote a Zeitoper for Frankfurt, Transatlantic (1930, originally titled Glare).
In Von Heute auf Morgen (1930) Arnold Schoenberg attempted to have the last word on the fashion: at the end a child enters and asks the reconciled parents "What are modern people?"