The pattern envelope says this about Butterick 5261:
An easy to wear raglan classic is perfect for any occasion. Try this feminine shirt jacket over a sharp blouse for the office or wear it with your favorite jeans for the weekend. This design can be made out of mediumweight to lightweight blouse fabric. This has a convertible collar and features a center back pleat, sleeves that gather into a slim cuff and a shirttail or straight hem.
*When did Butterick get so verbose! *LOL*
Since I don't feel like visiting hair and make-up today, Lulu will be modeling the shirt jacket. Here it is with a RTW tank top: