From Liesl + Co.:
This easy-to-sew and easy-to-wear pull-on, loose-fitting, sleeveless blouse features a keyhole back opening, side panels to provide a contrast fabric option, darts for shaping, and separate pattern pieces for A/B, C, and D cups to enhance fit. The pattern eliminates side seams for a fun and unusual take on a slightly boxy top, and it has a gentle shaped hem and bias facings at the neck and arms. This is a great pattern to showcase a favorite fabric.