In "Dr. Thorndyke's Case-Book" by Austin Freeman", a detective was talking to a doctor, who was summoned to check a dead woman, saying:
In the aspect of the room there was something strangely incongruous with the tragedy that had been enacted within its walls; a mingling of the commonplace and the terrible that almost amounted to anticlimax. Through the wide-open window the bright spring sunshine streamed in on the garish wallpaper and cheap furniture; from the street below, the periodic shouts of a man selling "sole and mack-ro!" broke into the brisk staccato of a barrel-organ and both sounds mingled with a raucous voice close at hand, cheerfully trolling a popular song, and accounted for by a linen-clad elbow that bobbed in front of the window and evidently appertained to a house-painter on an adjacent ladder.
Does "accounted for by" here mean "overshadowed by" or "its existence explained by"?