A starkly lit photo of Sini wearing the finished thing the sleeves are part of, which is an 18th century riding ensemble or gown. A slightly shorter petticoat of the same striped fabric and the coat-inspired dress part, which has a very low open neck filled out with an ivory with yellow flowers fichu, wide mantled collars, six pairs of buttons down the front, and long fitting sleeves. The hips are very very padded and wide, the waist looking small and conical in comparison. With the pale gray curly wig half down and half up, red lip, cheeks and powdered face, it's a reasonable approximation of a fashionable lady from the time, though a bit plain and dark. More like a witch pretending to be a lady.
https://eldritchcafe.files.fedi.monster/media_attachments/files/116/675/505/971/851/377/original/f9933cb153d1c691.jpg