Cynthia makes her first appearance in this coat.
It overlaps in the front and closes on the waistband, I assume by a button or hook-and-eye. We see Cynthia unfastening it at the beginning of Episode 2 when Molly shows her to her room.
While I am not positive, I wonder if one might alter Sense and Sensibility's Regency Spencer and Pelisse pattern for this coat, perhaps lengthening the waist a little and making the waistband closure as opposed to a closure on the front bodice. In Timely Fashion also shares some thoughts on this coat.