"García Lorca’s 1936 play appears in the collection Three Tragedies, making its genre explicit."
Well, no. Lorca's subtitle for this play is "Drama de mujeres en los pueblos de España." If after his death someone wants to put it in a collection called "Three Tragedies," that is fine, but that is an editorial decision made long after the author's death.
This is an article that points out that one of the similarities between Waiting for Godot and La casa de Bernarda Alba is they are both plays!