Like the window to the right of the main inner church doors, this window was originally part of Window 10, Jesus on the Cross, described in John 19.
John 19:26. When Jesus saw his mother and the disciple there whom he loved, he said to his mother, "Woman, behold, your son." Then he said to the disciple, "Behold, your mother."And from that hour the disciple took her into his home. John 19:26. (NABRE)